|“||Chris: "Kate! I know what you did. Put the gun down."
Kate: "I did what I was told to do."
Chris: "No one asked you to murder innocent people. There were children in that house. Ones that were human. Look what you're doing now! You're holding a gun at a sixteen-year-old boy with no proof he's spilled human blood. We go by the Code-- "Nous chassons ceux qui nous chassent."
Allison: "We hunt those who hunt us..."
Moments later, Scott leaps away as Allison freaks out over what she just saw. She practically collapses in her father's arms as she gets off the school bus. Meanwhile, Scott weeps in the woods. On the football field, Peter forces Stiles to abandon the injured Lydia, although he allows him to call Jackson to bring her medical help. Peter also notes that Lydia will become a werewolf if she survives the effects of the bite. At the Argent home, Chris Argent lays into his sister, Kate for leaving so many clues for Allison to find and dragging her into their secret world of being Hunters. He orders her to leave town with Allison and get her safely away. At the hospital, Sheriff Stilinski briefly suspects Jackson of harming Lydia until he learns that his son, Stiles brought her to the dance as his date. In a parking lot across town, Peter intimidates Stiles into locating Derek by tracking Scott's phone. Stiles even takes a moment to talk at length to Peter about Macs. Stiles discovers that Derek is being held beneath the Argent home. In gratitude, Peter offers to make Stiles a werewolf but he turns him down. As he leaves, Peter says he can tell that Stiles wants the power, he just can't admit it to himself.
Scott locates Derek on his own and he initially refuses to free him unless Derek aids him against Peter. To win him over, Scott shows Derek proof that Peter intentionally killed Derek's sister in order to become the Alpha Werewolf. Enraged, Derek brakes out of his final chain by himself and agrees to help Scott. At the hospital, Stiles finally arrives to see Lydia and he learns new information from his dad that allows him to figure out that Kate set fire to the Hale home years before. Shortly thereafter, Jackson and Stiles are both held by Mr. Argent and his fellow hunters. But Stiles is able to convince Argent of Kate's murderous actions against the Hales. Across town, Kate and Allison attack Scott and Derek with explosive crossbow arrows and briefly subdue them. Kate then announces her intent to kill both of them and she shoots Derek. Just before she can shoot Scott (over Allison's objections), Chris arrives and he forces Kate to stand down and spare Scott. Then the Alpha Werewolf, Peter Hale shows up and takes out everyone before dragging Kate inside. Allison follows them and she watches as Peter slits Kate's throat for murdering his family. Before Peter can turn on Allison, Scott and Derek confront him in a two-on-one battle.
Outside, Stiles and Jackson pull up just as the Alpha Wolf is defeating Scott. Stiles throws a molotov cocktail at the Alpha, which Allison ignites with her crossbow arrow. Even Jackson gets in on the act by throwing his beer bottle at the flames. The Alpha collapses and transforms back into a badly burnt Peter Hale. Allison and Scott then kiss and recommit to each other. Over Scott's pleas to let him cure himself, Derek emerges from the home and kills Peter to become the new Alpha Werewolf. Later, Jackson tracks down Derek and begs to be made into a werewolf. Derek smiles as he bares his fangs at him and jumps to him to bite him. At the hospital, Scott and Stiles visit Lydia and note that she isn't healing quickly or changing into a werewolf. Back at the Argent home, Chris and his wife realize that they will be pariahs in the town now that Kate's crimes have been exposed. And there are more werewolf hunters on the way, but the Argents don't seem worried about Scott anymore. Outside on the roof, Scott holds Allison in his arms as they watch the stars overhead.
- Tyler Posey as Scott McCall
- Crystal Reed as Allison Argent
- Dylan O'Brien as Stiles Stilinski
- Tyler Hoechlin as Derek Hale
- Holland Roden as Lydia Martin
- Colton Haynes as Jackson Whittemore
- JR Bourne as Chris Argent
- Linden Ashby as Sheriff Stilinski
- Jill Wagner as Kate Argent
- Ian Bohen as Peter Hale
- Eaddy Mays as Victoria Argent
- Melissa Ponzio as Melissa McCall (voice only)
- Jeff Rose as Mr. Martin
- Susan Walters as Natalie Martin
- Stephen Calhoun as Marcus
- Marvin Duerkhol as Cody
- Reese Riley as Jaysen
- The Argent Hunter Code ("Nous chassons ceux qui nous chassent," or "We hunt those who hunt us") is revealed for the first time in this episode. This Code will continue to play a significant role in future seasons.
- It is officially confirmed that Kate Argent was the main culprit of the Hale House Fire. This was first implied in Magic Bullet. As a result of this, the media ultimately blamed Kate for all of Peter's murders in the media as well, which the Argents didn't question out of a desire to keep their presence quiet, though they were not happy about this turn of events.
- Kate also stated that she was following orders by doing so, suggesting that her father, Gerard Argent, may have also played a role in the fire, or at the very least encouraged her to do it.
- Kate is killed by Peter Hale in retribution for the Hale House Fire in this episode.
- However, though it was believed that she died for good after he clawed her throat out, in reality, she was transformed into a Werejaguar due to how deeply he scratched her, and the accelerated healing she gained from this transformation ultimately resurrected her just prior to the full moon in Shape Shifted.
- Peter is finally killed by Derek Hale (with help from Jackson Whittemore, Stiles Stilinski, and Allison Argent), which causes Derek to become the Alpha, a rank he will maintain until Season 3's Alpha Pact.
- Allison and Scott rekindle their relationship after breaking up in Night School. This is also the first time that Allison tells Scott that she loves him, after Scott first told her the same in Formality.
- It is revealed that Peter killed his nurse, Jennifer, who was helping him with his plan to kill all of the conspirators in the Hale House Fire. Jennifer was last seen in Wolf's Bane.
- Lydia Martin neither turns into a Werewolf nor dies from rejecting Peter's Bite in this episode, which appears to be unheard of in the supernatural world. Lydia was attacked by Peter in Formality.
- It is implied that Jackson is given the Bite from Derek at the end of the episode, making him the first human Derek has turned since becoming an Alpha. Jackson has been seeking out the Bite since Wolf's Bane.
- Gerard Argent is referenced by Victoria Argent in this episode, though not by name. He will not make his first appearance until Omega.
- It is revealed that Peter lied about killing Laura Hale on accident, and that Nurse Jennifer purposely burned the spiral into the dead deer to lure her back to town so Peter could steal her power. It was first speculated that Laura was lured back to Beacon Hills by someone in The Tell.
- The title refers to Kate Argent, who broke the Argent Hunter Code by setting the Hale House Fire and attempting to kill Scott despite having no evidence that he had killed an innocent life.
- It is revealed that Scott's username and password to his cell phone account are both "Allison."
- Stiles was offered the Bite from Peter in this episode, but he declined, marking the first of several occasions where Stiles receiving the Bite was suggested by others.
- Kate Argent* - throat clawed out; killed by Peter Hale
- Peter Hale** - throat clawed out; killed by Derek Hale
- Argent House
- Allison's Bedroom
- Living Room
- Abandoned Parking Garage
- Hale House
- Beacon Hills Memorial Hospital
- Emergency Room
- Lydia's Room
- Beacon Hills Preserve
- "DJ Ease My Mind" by Niki & The Dove
- Kate drives Allison to the hospital to see Lydia while Scott hides in the exam room of the animal clinic.
- "If (Don't Ever Blame Yourself)" by Last Days of April ft. Tegan Quin
- Allison kisses Scott in front of the Hale House while he's shifted into werewolf form.
- "Of The Mountains" by Dan Deacon
- Derek breaks free of his restraints and tells Scott that he'll help him stop Peter.