In Currents, Lydia and Aiden were making out in Coach Finstock's office when suddenly, the fire alarm went off. After Aiden left first, Lydia stayed behind for a moment to get straightened up, but before she could follow him out, Cora appeared, revealing that she had been the one who pulled the fire alarm so as to separate her from Aiden. She remarked that Lydia didn't have very good taste in guys, and when Lydia asked her if she had a problem, Cora informed her that she had been sent by her older brother Derek Hale, Alpha of the Hale Pack, who had "kindly asked" that Lydia stop seeing Aiden.
Before Lydia could reply, Cora added that if she saw Aiden and Lydia together again, she would be pulling her tongue out of her head instead of the fire alarm. Lydia, unimpressed by Cora's threats, remarked that since her last boyfriend, Jackson Whittemore, was a "homicidal lizard," she was confident that she could handle a Werewolf. However, when Cora grabbed Lydia by the wrist and squeezed it tightly, Lydia began to get scared and demanded that she let go. When Cora continued to apply pressure to her arm, Stiles Stilinski appeared behind them and insisted that Cora listen to Lydia and let her go, which Cora reluctantly did.
Off-camera, the three discussed the fact that the Darach had captured Alan Deaton as their third "healer" sacrifice, and, since Deaton had saved them on numerous occasions, they agreed to work together to figure out where he was and save him before he could be killed. Stiles then decided to use Lydia's still-unknown psychic powers and divination to find Deaton's location. They began with a Ouijia board, with Stiles instructing all of them to put their fingertips on the pointer. A moment after Stiles asked, "Where is Deaton?" aloud, both Cora and Stiles opened their eyes and looked at Lydia expectantly. Lydia exasperatedly pointed out that she didn't know the answer before adding that she was under the impression that they were asking some sort of spirit. When Cora asked Lydia if she knew any spirits, Lydia looked over at Stiles and pointed at Cora before snarkily replying "Is she for real?"
With the attempt to use the Ouijia board was a failure, Lydia, Cora and Stiles moved on to Psychometry, a form of divination that involves seeking and gaining information through making tactile contact with personal objects. Stiles held out Deaton's keys to the clinic and asked Lydia to "feel out" for Deaton's location through the keys' energy. Lydia argued that she isn't a psychic, but still took the keys, though clutching them did nothing but alert her to the fact that they were cold.
Lastly, they decided to try automatic writing, where Stiles and Cora intended to have Lydia draw on psychic energy to intuitively write down answers. However, when Lydia immediately began sketching a tree, both Stiles and Cora became overwhelmingly frustrated. When Cora snidely asked Stiles, "Isn't she supposed to be some kind of genius?", Lydia, also losing her patience, pointed out that she was indeed a genius, she just wasn't a psychic. She then pointed out that they were wasting time bothering with Lydia when they should actually be talking to Danny Mahealani, a suggestion that Scott McCall, who had just appeared in the doorway, confirmed by pointing out that Danny was a target the previous night, but he wasn't a sacrifice.
The group decided to split up, with Cora and Lydia going with Stiles to talk to Danny while Scott went to see Allison Argent, who had important information about the human sacrifices. Afterward, Cora, Lydia, and the others met up at the Beacon Hills Animal Clinic to share what each group learned, with the focus being on the revelation that there are numerous telluric currents around and through the city of Beacon Hills based on information in Danny's physics report and the hints Scott received from Deucalion. When Lydia surmised that the locations of where the victims were captured and where the bodies were found were along the telluric currents, Stiles determined that where the victims were killed in-between. As Stiles and Lydia studied the map, Cora's face became horrified as she pushed Stiles' hand over the location of the First National Bank, revealing that Deaton was in the same bank vault where she was held captive for four months.
As the group rushed off to find Deaton, Cora received a text message from Vernon Boyd, which informed her that the plan that he and Isaac Lahey had made to protect Derek from the Alpha Pack failed due to Kali and the twins cutting the power. After a short debate, it was decided that Scott would rescue Deaton on his own while Cora and Lydia drove to Derek's loft with Stiles in an effort to save Derek, Boyd, and Isaac from the Alphas. When they arrived at the loft, they went to the room with the electrical controls, where Cora, Lydia, and Stiles looked around anxiously at the dozens of levers and buttons. When Cora asked what they should do, Stiles instructed them to pull all of the levers, which he, Cora, and Lydia did. Afterward, they rushed up to Derek's loft, where Lydia immediately stopped to a halt in the doorway upon seeing Boyd's lifeless body laying in the shallow water throughout the loft while Derek crouched over him. Cora was confused by Lydia's shock at first until she saw the tragedy for herself and instantly ran past her into the apartment and began sobbing over Boyd's body.
In The Girl Who Knew Too Much, Lydia reluctantly took Aiden to Coach Finstock's office at the high school to distract Aiden while Scott and Stiles questioned Ethan on the Alpha Pack's former Emissaries. However, before they could really talk, a Werewolf appeared outside of the office's door and scratched a spiral, the Werewolf symbol for revenge, on the frosted glass with the claws.
Believing it to be Derek Hale, who had it out for the Alphas following their role in the deaths of his Betas, Erica Reyes and Vernon Boyd, Aiden sought the Werewolf out while a scared Lydia begged him to stop and threatened to scream to get the attention of the others. Aiden refused to listen as they made their way into the boys locker room and demanded that if Derek wanted to fight him, then that was what he was going to get.
However, it was soon revealed that the Werewolf was actually Cora Hale, who, like her brother Derek, was furious at the loss of her friends Boyd and Erica. Cora appeared out of nowhere, partially-shifted into her wolf form, so quickly that she caught Aiden off-guard and got several good claw swipes into him before Aiden recovered and was able to fight back. Lydia watched the fight between Cora and Aiden in horror, especially when Aiden, having gained the upper-hand, grabbed a nearby bench-press weight and slammed it against Cora's temple before shoving her across the room, where she hit the wall under the sink. Ethan, Scott, and Stiles then ran in to pull them apart, with Ethan reminding his twin of the deal Kali made that forced them to wait until the next full moon before dragging him out of the room. All the while, Lydia crouched down to check on Cora, who was still recovering from the assault against her.
After the fight was over and the twins had left, Scott and Stiles joined Lydia in checking on Cora, who was bleeding badly on her temple from where the weight hit her and whom Stiles believed to be serious injured. Lydia insisted that Cora was not okay when Scott asked her how she was doing, and though Cora insisted that she was fine, she wobbled on her feet when she backed up and would have fallen if Stiles hadn't caught her. When Stiles asked Cora if she knew how "suicidally crazy" going after Aiden was, Cora shouted that she did it for Boyd, and that none of them were doing anything about it; Cora then left herself after adding that though they thought they could stop people from getting killed, all they really did was find the bodies, a statement that appeared to be specifically targeted toward Lydia and her yet-unknown powers causing her to find victims of the sacrifice ritual after they died.
Cora was taken to Beacon Hills Memorial Hospital after she collapsed at the Stilinski House during Cora and Stiles' attempt to confess the existence of the supernatural world to Noah Stilinski, as they believed his status as a police officer and the Sheriff of Beacon County made him a target for the "guardian" trio of sacrifices. While Derek was in the hospital checking on Cora, they both heard Lydia's extraordinarily loud Banshee scream when Jennifer Blake tried to kill her, which confirmed that Lydia was, in fact, a Banshee.
In Lunar Ellipse, Cora was at Derek's loft with Peter and Derek (the latter of whom was still recovering from having donated his Alpha spark to heal Cora of her Mistletoe poisoning) when Lydia and Ethan arrived to warn Derek that Kali and Aiden were on their way to kill him, as per their vow to kill him and the rest of his pack if he didn't kill his Betas and join the Alpha Pack.
Derek, Peter, Ethan, Cora, and Lydia then debated their options. Peter insisted that Derek needed to leave Beacon Hills, since his demotion to Beta status combined with his previous inability to beat Kali as an Alpha meant that his chances of winning a fight against her meant he was unlikely to survive the battle. Cora, on the other hand, argued that Derek wanting to take the chance, that she was fine with that, as long as he would be dying for something meaningful. Lydia, listening to their arguments, remained silent as Derek made it clear that he was appalled by the insinuation that he would lose, and Peter remarked that Lydia likely had an idea of the outcome of their match. When Cora and Derek asked her what she felt, Lydia admitted that she felt as though she were standing in a graveyard.
Lydia and Ethan then stayed behind at the loft to buy Cora and Derek some time to flee Beacon Hills, with Lydia even going so far as to taunt Kali about her toe-claws to stall them as long as possible. Unfortunately for them, Jennifer Blake, the Darach who had, at this point, committed twelve human sacrifices in order to gain the powers needed to defeat the Alpha Pack once and for all, battled the Alphas in the loft after jumping through the skylight. The battle ended after Jennifer snapped Ethan and Aiden's neck in their merged form and slaughtered Kali by telekinetically shoving hundreds of shards of glass into her body. Jennifer then turned on Lydia, who asked her what she wanted from her before being told that she needed her to do what she did best-- to scream. Lydia's Banshee-scream was so loud that Cora and Derek heard it on their way out of town; when Cora asked what the sound was, Derek informed her that it was Lydia before insisting that they needed to go back.
When Derek and Cora returned to the loft, Derek debated with Jennifer about his involvement in her plan to kill Deucalion while Cora immediately rushed over to comfort Lydia, who was still in shock after watching Jennifer kill both Kali and Ethan and Aiden's merged form. Though Derek was initially resistant to helping Jennifer, he ultimately agreed to do so in order to save both Scott as well as the final three sacrifice targets-- Noah Stilinski, Melissa McCall, and Chris Argent. Once Derek and Jennifer left, Cora helped Lydia to her feet and pulled her toward the loft's door, stating that they needed to get away from there as soon as possible. However, they both stopped in their tracks when they saw that Ethan and Aiden fell out of their merged form and were stirring slightly, indicating that they were still alive.
Cora and Lydia then worked together to get the twins to the animal clinic in hopes that Alan Deaton could save their lives, assisting him in clearing off the two steel tables so that they could lay each of the twins on them and get to work in healing them. When Cora asked if Deaton was capable of bringing them back, Deaton grimly replied that it was possible, but only if their bodies started healing on their own, before he injected each of them with a substance to help trigger that healing process and put them both on supplemental oxygen. Both women were relieved when the twins awakened and survived their injuries.
A short time after the defeat of Jennifer and the Alpha Pack, Cora left Beacon Hills and returned to her former pack in South America, with Derek and Peter accompanying her there. Cora remains there to this day, and has seemingly had no contact with Lydia since this point.