In Tattoo, Isaac was seen unconscious and badly injured in a warehouse where Braeden, a mercenary, dragged him to safety. She quickly used a car battery to restart Isaac's heart and awaken him, causing his eyes to glow gold as he groaned. Braeden insisted that he stay quiet before helping him stumble to her motorcycle, during which time Isaac realized he had claw wounds on the back of his neck as well as slashes across his chest and abdomen. When he murmured that he didn't remember anything, Braeden explained that the wounds on the back of his neck were from their claws, which is how Alphas share and steal memories, before getting him onto her bike and instructing him to hold on tight to her no matter what happened.
Braeden then set off to get herself and Isaac to safety, but after only a few minutes, Isaac heard something behind them and turned to find they were being chased by twin Alphas, Ethan and Aiden. He insisted that they needed to go faster, and Braeden put the pedal to the floor as she sped away from them, easily dodging the Alphas' strikes as they swiped at them. Unfortunately, they ended up accidentally driving down several dead-end streets and alleys, the last one leaving Braeden no choice but to drive them through a wall of windows into another abandoned warehouse. The force of the impact knocked Isaac unconscious, causing him to slump over and unbalance the motorcycle enough to knock the bike and the two of them onto the floor.
With both of them injured and laying on the floor, the twins stomped toward them and began to disrobe. The sight of the brothers merging together into one extra-large Alpha caused Isaac to briefly regain consciousness, though he was still too weak to do anything but crawl away from them. Fortunately, Braeden was armed and told Isaac to duck out of the way before shooting at the twins with a modified, military-grade stun gun, whose electricity shocked them and forced them to separate once again. Realizing that they were outmatched by this weapon, the twins vanished, and Braeden snapped, "I thought I told you to hold on!" to Isaac before he fainted.
The two were eventually found by police and brought to Beacon Hills Memorial Hospital by paramedics, where they were immediately greeted by the nurse Melissa McCall. Melissa wasted no time asking Isaac what had happened and why he wasn't healing, but Isaac assured her that he would recover soon enough and insisted that Braeden was in worse shape, leading Melissa to leave him to check on her instead.
Once Isaac had been admitted, Melissa returned to check the deep claw-gashes across his chest and abdomen, which were smoking slightly as they slowly began to heal.
Realizing that the doctors would soon notice the fact that Isaac was healing much faster than any normal human should, Melissa began to panic, and when Isaac suggested that they just keep his injuries covered up with bandages, she reminded him that he was scheduled for surgery and that it would be difficult to keep his condition a secret. When Isaac asked her if she called Derek, Melissa admitted that she had done so many times and couldn't get in touch with him before asking him if he had any other "emergency Werewolf contacts." Isaac sighed and said that he did before instructing her to call Scott.
Sometime later, Sheriff Stilinski arrived to ask Melissa if he could speak with Braeden since Isaac was supposedly suffering from amnesia and couldn't remember anything about the event. Once they had left, another member of the Alpha Pack, Kali, went into Isaac's room disguised as a nurse and asked him how he was doing. Since his memories had been stolen by the Alphas, he didn't immediately recognize her as she stopped him from trying to sneak out of the hospital to avoid having his supernatural identity exposed. She then injected a large number of anesthetics into his IV to knock him out, insisting that they couldn't let him get away again.
Just before Isaac lost consciousness, he looked down at the floor and saw that her toenails were sharp claws, just like the ones on her fingers. Once he was taken to surgery, Dr. Vandenburg was appalled when he removed the dressings over Isaac's wounds to find that he was uninjured, and berated the other nurses for wasting his time before leaving to smoke a cigarette, leaving Isaac free to be captured by another member of the Alpha Pack, Ennis, disguised as a surgical technician.
Ennis had just transferred the still-unconscious Isaac to a wheelchair and was about to leave with him when he was spotted by Scott McCall, who wasted no time in wolfing-out and diving into the elevator before the doors could close. However, Scott was easily defeated by Ennis, who reminded him of his Alpha status as he grabbed him in a choke-hold while Isaac, still asleep in his wheelchair, rolled around the elevator. Fortunately, Derek Hale arrived and saved both Scott and Isaac from Ennis before the three left to go to the Hale House ruins.
Once there, Derek laid Isaac on a table while searching under the floorboards for purple flowers that resembled wolfsbane, claiming that they would help heal the internal wounds caused by an Alpha. After Scott and Stiles had forced Derek to confess that they were dealing with the Alpha Pack, lead by a powerful Alpha named Deucalion, Isaac finally awakened from the anesthesia Kali had given him and immediately demanding to know where "the girl" was, though neither Derek, Scott, nor Stiles knew about whom he was speaking.
In Chaos Rising, Isaac met with Derek at the loft to discuss how to recover the memories the Alpha Pack had stolen from him during his brief capture. Derek knew of a ritual that could help, but since it was a risky procedure that he had never performed before, he decided to call his uncle Peter to help them. Before Peter arrived, Isaac mentioned that he didn't like Peter (to which Derek replied that no one liked Peter) and insisted that since Scott didn't trust Peter, he wasn't really fond of the idea of trusting him either. Just then, Peter arrived and reminded them that while he was still weakened following his resurrection, his hearing still worked, making a point to insist that they tell him what they feel to his face.
After sitting Isaac in a chair, Peter briefly explained the ritual he was about to perform, which was the same ritual the Alphas used to take Isaac's memories, and which was typically only performed by Alphas in general due to the amount of control needed to avoid paralyzing or killing their target. Isaac became nervous and asked him if he had ever killed anyone by doing it before, but before he got an answer, Peter stuck his claws in the back of Isaac's neck and delved into his memories. Both Isaac and Peter were shaky when they came out of it, and Peter admitted that he only got bits and pieces of what Isaac had seen. However, what he did manage to glean from Isaac's memories was that Deucalion and the others planned to kill Erica and Boyd at the next full moon, which was the following evening.
Not trusting Peter's assessment and knowing that they needed more information before they staged a rescue, Derek, Isaac, Scott and Stiles went to the animal clinic to see if Alan Deaton had any ideas. He explained that he knew of a ritual that would help Isaac himself remember his repressed memories, though he warned that it was dangerous due to it requiring that his heartbeat was slowed to a near-death state. Isaac ultimately agreed to the ritual, which involved getting into an ice bath until his pulse slowed and allowed him to partially-transform into a trance-like state. Deaton began to ask him questions about what happened, but Isaac, seeing something in his memories that frightened him, became increasingly agitated, though he was able to describe the location where Boyd and Erica were being held.
When Derek, losing his patience, demanded more precise answers, Isaac became overwhelmed by the different stimuli, and his mind was so flooded with memories that it caused him to briefly narrate them to the group before he snapped out of it, though he had no recollection of what he had said once he came to. As Isaac got out of the tub and wrapped himself in a blanket, he explained that he saw that Boyd and Erica were being held at First National Bank. When he saw the horrified expressions on Deaton, Derek, Scott, and Stiles' faces, he asked them what was wrong, leading Stiles to realize that Isaac had no idea what he said before he woke up.
After a moment of hesitation, Stiles admitted that Isaac had said that the Alphas locked him in a closet with a dead body in it, which he quickly realized was Erica's. After this revelation, Isaac helped the others get a general idea of what they needed to do to rescue Boyd and explained the little he knew about the other girl in the vault with him who they had initially believed was Erica. Isaac was certain that the girl was a Werewolf like them, though none of them knew at this point that the girl was actually Derek's sister Cora Hale, who he believed died in the Hale House Fire.
In Fireflies, Isaac, who was still recovering from his hypothermia, was seen in the woods when he joined Scott in chasing down Boyd and Cora, who were rabid due to feeling the full moon for the first time in four months after being trapped in a hecatolite-lined bank vault.
Isaac believed he had the upper-hand against Cora when he flipped out of a tree and tackled her to the ground, but she quickly jumped to her feet and shoved him so hard he flew into the tree before bouncing off and landing on his stomach on the ground. Isaac and Scott then caught up with Derek to discuss what they needed to do to stop Boyd and Cora from hurting innocent civilians, and was offended when Scott suggested that they needed better help than just Isaac himself. However, upon learning that the two rabid Werewolves had supposedly killed a lifeguard (who Lydia Martin had just found in a Banshee fugue state, though she did not realize her true nature at the time), Derek and Isaac agreed to Scott's idea to seek out additional help.
Isaac and Derek accompanied Scott to a grocery store so Scott could approach Chris Argent, who had retired from hunting, and ask for his help. Though Scott insisted that they needed his assistance due to his knowledge of how to capture a Werewolf without killing them, it was obvious that both Isaac and Derek doubted the man would help them. While they waited on Scott, Isaac asked Derek about his sister, implying that he had a romantic attraction toward her, but when Derek shot him a look, Isaac anxiously backtracked on his comments. Surprisingly, Chris agreed to help the young Werewolves, leading the four to go to the Beacon Hills Preserve so he could show them how to track Boyd and Cora.
After explaining that the Derek, Isaac, and Scott, as Werewolves, were more adept at tracking by scent than by physical footprints, he sent each of them out with ultrasonic emitters in order to corral Boyd and Cora where they wanted them to go. Upon deciding to lock the rabid Werewolves in the boiler room of the high school (under the mistaken impression that it was empty, since it was the middle of the night), the group worked together to lure them there.
Isaac, as one of the fastest runners of the group, volunteered to run around the school to lock Boyd and Cora inside so Derek and Scott could trick them into going into the boiler room. However, when he got there, he was surprised to find Allison Argent, who had come to help without anyone knowing and who shot flash-bang arrows at Boyd and Cora until they ran into the school, allowing Isaac to lock the doors behind them. When Isaac turned to look at Allison in awe, the young huntress smiled for a moment before realizing she had been caught and running away.
Isaac kept watch outside while Derek and Scott dealt with the fact that they had accidentally trapped Boyd and Cora inside the boiler room with the new English teacher, Jennifer Blake, and when Isaac realized that the sun was coming up, he rushed toward the boiler room to inform Scott of it. Isaac and Scott then wasted no time going into the locked boiler room to make sure everyone was okay, where they were relieved to find Derek bloodied but otherwise fine, surrounded by Boyd and Cora, who had passed out from exhaustion the moment the moon had set. Derek tiredly instructed them to take Boyd and Cora back to the loft while he made sure Jennifer was okay.
In Unleashed, Isaac returned to school for the first time since he was captured by the Alpha Pack and attended early morning cross-country practice. Upon seeing him, Coach Finstock berated him for missing earlier practices before reminding the team members that membership on the cross-country team was mandatory for all lacrosse players to ensure they didn't get "flabby" on the off-season, but when he turned to see the quite-muscular Isaac and Danny Mahealani getting changed nearby, Coach quickly shut up and left them to get ready for practice.
Isaac and the rest of the team gathered behind the high school in the Beacon Hills Preserve to go on their morning run, and Scott was about to approach him when Isaac saw Ethan and Aiden and recognized them as being among the Alphas who had captured him. Scott warned Isaac to let it go, but Isaac became too furious to listen to him when the twins began purposely goading him. Isaac began to sprint into the preserve as the twins chased after him, with Scott trying his best to keep up and keep Isaac from getting himself killed as well. The twins managed to trick Isaac into stopping, where they tackled him and pulled him off the trail into a more wooded area.
Ethan held him down while Aiden threatened to break every bone in his body, but before he could harm Isaac further, Scott arrived and punched Aiden in the face so hard that his jaw temporarily broke. The four wolfed out and were about to fight when the sound of screaming nearby scared them out of fighting, and they instead decided to rain-check their battle in favor of finding out what was going on. They ran toward the source of the screaming to find that the body of a young ROTC student, Kyle, had been found tied to a nearby tree around his neck with his throat slashed, his head beaten in, and his body covered in blood.
Isaac and Scott quickly caught up with Stiles to discuss their theories, and Isaac wasted no time blaming the death on Ethan and Aiden. Stiles, on the other hand, argued that the lack of claw marks indicated that the death had nothing to do with werewolves, and Isaac and Stiles eventually turned to Scott to each convince them to take their respective sides. Scott, not wanting to get in the middle, first pointed out that Isaac made a good point, as he believed Stiles' theory that "virgin sacrifices" was kind of unbelievable, but when Stiles reminded him that their werewolf powers were also unbelievable, which led Scott to concede that they both had good arguments. Isaac, however, was not thrilled by Scott and Stiles' lack of desire to go after the twins without more proof and vowed to get revenge on them himself.
In Frayed, Isaac saw Scott getting ready to leave the McCall House and stopped him, noticing his friend was nervous and asking him where he was going. Scott, who planned on having a parley with Deucalion in hopes of brokering a truce between their packs, tried to keep Isaac out of it by lying and saying he was getting Mexican food for dinner, but Isaac went with him anyway to the meeting place, an abandoned mall somewhere in Beacon Hills.
However, upon their arrival, it soon became clear that the meeting had taken a turn when it was revealed that Derek Hale and the rest of the Hale Pack, knowing that Scott was going to attempt a truce, crashed their meeting in hopes of killing Deucalion and, with him, the threat the Alpha Pack posed against them. Unfortunately for them, Deucalion also anticipated a fight and brought his fellow Alphas along with him, leading the two groups to begin to fight each other. Isaac immediately wolfed-out and began to fight Ennis, forcing Scott to transform and do the same to back him up, but both Betas were quickly overpowered by the Alphas, as were the rest of the Hale Pack.
Deucalion gave Derek a choice to either kill Boyd or Cora in exchange for allowing the others to go, and when Kali scoffed at Deucalion's attempts to recruit Derek, whom she saw as just an "Alpha to a pack of useless teenagers," Deucalion remarked that some had more potential than others and looked over at Scott. Before Derek could do anything, Allison Argent appeared and began shooting flash-bang arrows around the large area, giving the Hale Pack another chance to get on top, and this time with the Alphas caught off-guard. Isaac once again teamed up with Scott to take out Ennis, and when the Alpha fell over the railing and pulled Derek down with him, Isaac was the first one there to comfort Scott on what they believed to be Derek's death.
The next day, Isaac and the rest of the cross-country team set off for a match out of town on the bus, where he instantly noticed Vernon Boyd's despair regarding the previous night's events; though he told his friend to stop thinking about it, adding that there was nothing any of them could do to change things, Boyd asked him if he really believed that, causing Isaac to sigh before falling silent.
Several hours later, when Boyd lost control over his anger and transformation and nearly started a fight with Ethan Steiner, whom Boyd blamed for Derek Hale's supposed death, Isaac assisted Scott in talking him down, taking note of the fact that Scott's severe injuries from the previous evening had yet to heal and beginning to worry about his new friend. When the team stopped at a rest-stop on the way to the match, Isaac learned from Stiles that Scott's body was rejecting his healing process and became so concerned about losing another friend that he began violently punching Ethan in front of the rest of the team, buying them more time to get Scott patched up, just as Stiles intended. No one was able to get Isaac to stop except for Scott, who roared at him (albeit in human form) to get him to come back to his senses.
In Motel California, Isaac was among the many students on the Beacon Hills cross-country team who stopped to stay at the Glen Capri Motel when their match got rescheduled. Isaac roomed with his friend and packmate Vernon Boyd.
However, unbeknownst to any of them, they had been exposed to powdered purple wolfsbane on the bus, which caused all of the Werewolves in attendance to begin experiencing terrifying hallucinations. Isaac was alone in his and Boyd's room when he suddenly heard something and sat up in bed. Just then, he began hearing his father, Mr. Lahey's voice asking him to hand him the seven-sixteenths wrench, seemingly a reproduction of a memory Isaac had with his father. Isaac looked apprehensive when Mr. Lahey's voice loudly berated him for handing him the nine-sixteenths wrench and asked him if he knew what the difference was.
Seemingly in a trance, Isaac began repeating what his father said during this occasion, "A stripped bolt!", before asking his father what he wanted him to do. Mr. Lahey's voice sharply told him to shut up, which led Isaac to mindlessly tell himself to shut up before muttering that he couldn't fix this now. Mr. Lahey's voice then stated that he couldn't even keep the nut and bolt closed before instructing Isaac to grab the chains and get into the freezer where he was locked whenever Mr. Lahey wanted to punish him. When Isaac resisted these orders, Mr. Lahey screamed at him, causing Isaac to flop backwards and bury his head under his pillow. After a moment, he slowly removed the pillow and looked around, only to find to his horror that he was inside the freezer, whose door slammed shut on him as he began to scream in fear.
Later on, when Stiles and Lydia found Boyd pinned down in their full bathtub with a safe pinning him down so he would drown, they realized that using fire or heat could help snap the Werewolves out of their trance after using a road flare to get Boyd to save himself. Lydia found Isaac hiding under the bed, still terrified but trying to wait out the effects of the wolfsbane; it should be noted that Isaac was the only Werewolf who didn't attempt to commit suicide because of the wolfsbane, likely due to his self-preservation instincts after suffering abuse from his father for so long. Stiles was then able to snap him out of it with another road flare, and Isaac spent the rest of the night sleeping in the bus with Boyd, Stiles, Lydia, Scott McCall, and Allison Argent, as all six were too afraid to stay in the motel, which they believed to be haunted.
In Currents, Isaac joined his friend and housemate Scott in keeping watch over their mother Melissa while she slept, as they were worried that she would be a target for one of the Darach's "Healer" sacrifices. Melissa found them both fast asleep in front of her bed and immediately raised her voice to wake them up and ask them what they were doing in her room. Isaac sheepishly admitted that they were protecting her, and when Melissa was confused about this due to the fact that they were both asleep, Scott and Isaac briefly argue about who was supposed to be on watch last, with Isaac finally confessing that he may have fallen asleep while on watch last; though he briefly seemed afraid of Melissa's reaction due to his history with his abusive father, Melissa simply smiled and called them both her heroes.
Melissa went on to say that, since she isn't a doctor, she shouldn't be a target, but Scott reminded her of her impressive procedure to save Danny Mahealani from tension pneumothorax the previous night to emphasize that the ritual called for "healers" and that Melissa was definitely a healer at that time. Tired, Melissa assured them that she was not a target of anyone at this moment in time and instructed them to get ready for school.
However, when Isaac learned that the Alpha Pack had tagged Derek's loft as a warning that they were coming for him that night, Isaac and his packmate Boyd decided to leave school early so they could help him. Derek immediately instructed them to go back to school when they arrived at the loft, but Isaac jokingly argued that they couldn't, because they were both "incredibly and unbelievably sick"-- Isaac allegedly suffering from a migraine, and Boyd allegedly suffering from explosive diarrhea. Boyd reiterated that they were there to protect Derek, which led him to scoff and retort that he was in trouble, then, but Isaac assured him that Boyd had a good plan inspired by his and Erica Reyes' time being tortured with electricity by Gerard Argent, only on a larger scale.
Derek and Isaac then stood by and listened as Boyd explained his plan, which involved flooding the loft and putting electrical cables in the water so that it would electrocute anyone who walked through the door. Isaac pointed out that this was especially true for someone like Kali, who always walked barefoot so she had use of her toe-claws. Once the boys began putting their plan into effect, Isaac asked Boyd for confirmation that the set-up would kill the Alpha Pack, and Boyd, unsure, stated that he hoped so.
Once the loft was flooded, each of the wolves stood on a wooden palette in various points of the loft, keeping them above water to protect them from the electricity. The three sat waiting for a long period of time before Isaac, getting bored, looked over at the power console and saw that the light wasn't flashing like it normally did and brought it to Derek's attention. When Derek confirmed that the light should be on, Isaac asked him what it meant that it was off, leading Derek to grimly reply that it meant someone shut off the auxiliary power to the building.
Just as Boyd, concerned, asked if the main power was still on, his question was answered as the lights to the loft shut off completely, revealing that the Alphas had somehow anticipated their plan and shut off the building's power ahead of time to protect themselves. This was made clear when Kali, Ethan, and Aiden came into the apartment, with the latter two dragging in Derek's love interest Jennifer Blake to make matters worse. When Isaac anxiously asked Derek what they were going to do now, Derek's eyes flashed bright red as he growled, "We fight."
Isaac, Boyd, and Derek watched as Kali swaggered toward them, purposely walking through the electricity-free water, and admitted that her first idea was to find Derek and kill him wherever he stood after Ennis died, but she realized it wouldn't be that easy when she remembered that he surrounded himself with teenagers like Isaac and Boyd. So, she proposed an ultimatum-- Derek could fight her without any assistance from his packmates, or the twins would tear Jennifer apart. Derek quickly agreed to this fight and threatened to rip her throat out with his teeth before silently ordering his Betas to sit on the sidelines with the twins and Jennifer, whom the twins were holding in a choke-hold.
Isaac and Boyd stood back and watched with concern as Derek and Kali began to fight, and though Derek started off strong, it soon became clear he was no match for the augmented Alpha. While Isaac tried to calm down Jennifer, Boyd texted Cora to tell her how their plan failed, which caused Cora, Stiles, and Lydia to rush to the loft to help. As soon as they arrived, they went to the electrical room and turned on all of the switches, not realizing that Derek and Kali (along with Boyd, who had disobeyed Derek's orders and jumped in to help) would all be electrocuted by doing so.
With the three weakened from the massive amount of electricity they were exposed to, Isaac took advantage of the twins leaving to investigate to grab Jennifer protectively. Unfortunately, this just served to infuriate Kali, who forced the twins to grab Derek's wrists while his claws were still extended and impale them into Boyd's chest, knowing that his healing ability would be disabled or at least weakened from the electrocution. Isaac and Jennifer clutched each other in horror as Derek unintentionally stole Boyd's power, just as the Alphas intended.
Before Kali left, she advised Derek to make the smart choice and kill the rest of his Betas in order to join the Alpha Pack, assuring him that if he did not do so by the next full moon, she would be back to kill them all. Isaac then joined in Derek, Cora, Stiles, and Lydia mourning Boyd's death as his body continued to lay on the floor of Derek's loft.
In The Girl Who Knew Too Much, Isaac was climbing up the side of the Argent Apartment building to sneak in when suddenly, Allison sensed him outside her window and quickly grabbed her Chinese ring dagger before pulling him into the room and pinning him flat on the ground. She initially thought it was an intruder, so she was shocked to find that it was actually Isaac she just caught and was holding with her dagger to his throat, though she didn't move out of her position. She demanded to know what he was doing, and Isaac began to stammer that Allison hadn't been at school when Allison realized that Scott sent him to check up on her. Isaac, who seemed to be there of his own accord, suggested that Scott might be worried about her, and when Allison reminded him that she could take care of herself, Isaac smirked and replied, "Yeah, I've noticed... More than once," causing Allison to smile and finally get up off of him.
Off-screen, Allison seemed to have filled Isaac in on everything she had learned about the Darach and her father Argent's knowledge of the ritual since the events of Currents. Isaac was shocked to hear that Argent might be their serial killer, but Allison admitted that she wasn't sure yet and hoped he wasn't. "You hope he isn't the serial-killing dark Druid who's been slashing people's throats?" Isaac asked with a wry smile, causing Allison to sigh in exasperation and ask him if he was going to help her or not, which he agreed to do. She went on to show him the map on Argent's desk that had all of the locations of the kidnappings and body-drops marked in UV ink before pointing out that there were five more bodies to be found, but she wasn't able to find any indication of who it would be.
This gave Isaac the idea to take a few steps back away from the desk to look at the map from afar; when Allison asked him what he was doing, he explained that his father taught him to stand back and look at the whole picture, because from that vantage point it is easier to see things one wouldn't notice if they were focused too much on small details. Allison did just what Isaac said, and Isaac was noticeably affected by how close Allison was standing next to him, taking a moment to look at her face while she was busy staring at the desk. After a moment, she noticed the carving on the top of the desk and removed the map to reveal a symbol that Allison identified as a Celtic five-fold knot. When they used the UV light to look at the knot, they found "Virgins," "Warriors," "Healers," "Philosophers," and "Guardians" written in UV ink within each of the circles, which revealed that the latter two would be the last five people targeted for the sacrifice.
While the two were investigating, another person-- a history teacher at Beacon Hills High School named Mr. Westover-- was taken right from the school, and his disappearance was discovered by Lydia Martin while in a fugue state. This seemed to solidify Allison's belief that her father was the killer, and she grimly stated that they had to stop him, much to Isaac's concern. Isaac began to argue that if he was actually committing the murders, but Allison cut him off and reminded him that there was no "if," since her father seemingly knew and planned everything. She suddenly got another idea and began looking at the map of the Telluric Currents, as they knew Mr. Westover was taken from the school, which meant that there had to be another place on the map where his body would be dropped, eventually finding a new mark on the map at a Telecommunications Tower.
The two drove in Allison's car to the telecom tower, where Isaac, concerned, asked Allison if this was really the best idea and if they shouldn't involve Scott. However, Allison simply stated that he needed to stay behind her and stay quiet, pulling out her ring daggers to emphasize her point before she departed from the car, causing Isaac to mutter, "Oh, this is so not gonna end well..." before he got out of the car himself.
As they were walking toward the tower, Isaac quietly informed Allison that if Argent tried to kill him, he would be defending himself, but Allison, focused on the task at hand, absentmindedly retorted that if Argent wanted him dead, he'd be dead, which seemed to hurt Isaac's pride a little. Just as Allison was about to proceed into the building, Isaac reached out and grabbed her by the arm to stop her, as he had just caught the scent of blood; when Allison asked him where it was coming from, Isaac admitted that he still wasn't great at tracking by scent yet before guessing the direction it seemed strongest. Allison saw movement in a nearby room and immediately ran head-first into it, forcing Isaac to chase her from behind in an effort to stop her.
Just as they entered the room, the Darach appeared behind a chain-link fence where she had tied up Mr. Westover and had just strangled him with a garrote right in front of them before hissing and running away. Before Allison or Isaac can react further, Argent's voice was heard behind them telling them to get down so he could begin shooting at them with his dual Desert Eagle handguns. Isaac covered Allison with his body while Argent began shooting, and shortly after he reloaded, Argent ordered the two to go help Mr. Westover, though they were both horrified to find that he was already. Allison quickly realized that they were wrong-- since Tara Graeme, a Sheriff's deputy, was the first of the trio, they assumed it was "guardians," but it was really "philosophers" since Tara was also a teacher before she was a cop.
Allison and Isaac were shocked to learn that Argent had been tracking the Darach the entire time, and Argent took the opportunity to bitterly point out that he was this close to catching them had they not interfered. Isaac watched as Allison and Argent argued about the various lies they had told one another about staying out of the supernatural world before he finally cut them off and pointed out that now was not the best time for a "family meeting." When Isaac reminded them that there was still one more teacher who was going to be sacrificed if they didn't do anything, Argent realized that they would be at the recital, leading the three to leave for the school.
Isaac, Allison and Argent watched the recital from the back and were all unnerved by the creepy feeling caused when the orchestra and the choir began to play a haunting tune. The audience erupted into chaos when one of the piano strings snapped and slit the throat of the recital pianist, causing her to collapse dead on the floor, but as everyone fled from the auditorium, Isaac and the Argents went to the stage to get a better look. Allison was horrified when she saw that the pianist's throat was not only pouring blood, but also digested mistletoe, which told her that this was the Darach's doing as well.
When Lydia Banshee-screamed in hopes of preventing herself from dying at Jennifer Blake's hand when she revealed herself to be the Darach, Isaac was among the Werewolves in attendance who heard it and was forced to cover his ears in the auditorium from how loud and earsplitting the noise was. While they were occupied with the recital pianist, Sheriff Stilinski was captured by Jennifer to be the first of her "Guardian" trio of sacrifices, the last set needed to be performed before she had the power to attack the Alpha Pack head-on.
In The Overlooked,
In Alpha Pact,
In Lunar Ellipse,