The episode begins with Kira waking up in her cell in Mexico. When she finds the door is open, she wanders down the passageways in search of Scott. But when she finds him, the Berserker has already taken over and he attacks her.
Then Kate shows up and tells Kira her story. After she escaped the Calaveras, she was drawn to this temple, the name of which means “Smoke and Mirrors.” The Berserkers helped her survive, and she realized that she could not only control them, but create them as well.
Kate then decides to test Scott’s loyalty and tells Scott to kill Kira. He then stabs Kira.
Back in Beacon Hills, Stiles attempts to convince his father they need to go to Mexico. Sheriff Stilinski wants to go the lawful route, but Stiles is willing to do anything to save his best friend’s life. Luckily, they come to an agreement, with the Sheriff getting in touch with other offices to see if he can learn anything. If he can’t, he’ll head to Mexico with Stiles.
Derek and Braeden are packing up all the guns they can find. Derek doesn’t believe he’ll come back from this mission, but Braeden isn’t okay with that.
That’s when Peter comes in. He says the Berserkers are nearly impossible to kill, so they’re going to need everyone. At the same time, Stiles is searching for something for Malia to smell so she can help track Scott. Liam shows up, and they reluctantly let him come along.
The group meets in a warehouse with a prison transport van (because apparently Braeden is actually a U.S. Marshall) and discuss their plans. Lydia is getting Kira’s jacket for Malia to use to track her down, but unknown to the rest of the group, she’s attacked by a Berserker. When they can’t get hold of her, Liam sends Mason to look for her while the rest of them get on the road.
In the van, Derek hands Liam his family’s “ancient” talisman and gets Stiles to help him lie to calm the beta down. Kira’s mom appears to Kira while she’s dying from the wound Scott inflicted. Kira’s mom tells her how to heal, and it’s with pain. Kira breaks a piece of obsidian from the wall to jump start the process.
Back at the school, Mason wakes up and is greeted by Lydia. The Berserker threw them in the room together, and Mason picks up on the fact that she keeps referring to the Berserker as an ‘it.’ She tells him it’s not human.
Liam continues to transform, and he soon gets free. In the other car, Peter tells Malia being human doesn’t mean she’s in control. Things get close in the van with Liam, but Stiles saves the day by getting Liam to repeat Satomi’s mantra of “the sun, the moon, the truth.”
Before they can get too excited, the group arrives at La Iglesia, and as soon as Derek opens the door, he gets attacked by a Berserker and is severely injured. He tells the others to go save Scott.
Braeden stays with Derek while the others go after Scott and Kira. Stiles gets a call from his dad, who is at first furious but then understanding. Stiles sends him after Lydia and Mason. Parrish, Chris, and the Calaveras show up and start a showdown with Kate and her creatures. Meanwhile, Kira tells Stiles that Scott is a Berserker.
And then Derek smiles and closes his eyes…
Mason and Lydia go after the Berserker with a baseball bat. That doesn’t work, but luckily the Sheriff shows up and saves them. That’s when Lydia figures out that it was all a distraction to keep her in Beacon Hills in order to stop her from telling the others that they’re actually fighting Scott.
As the group continues to fight Scott, Kira and Stiles show up just in time to save them from killing him. But when he pins Liam up against the wall and Liam says “You’re not a monster. You’re a werewolf. Like me.”
When Scott finally breaks free of his Berserker guise, he comes to the conclusion that Peter is actually behind everything. He’s the one that taught Kate everything she knew about the Berserkers and her own powers. He did it all to restore the power of his family. But it’s not all altruistic — he did it to restore the power to himself.
When things look the worst for everyone fighting against Kate, a black wolf jumps into the fray and tears her down. Derek shifts back, and we find out that he didn’t die, he was just evolving. He leaves Kate alive, and instead kills a Berserker. Chris shoots Kate, and she just barely escapes.
Back in the tunnels, Peter and Scott are fighting. Peter seems to have the upper hand, until Scott realizes that he’s not just fighting for himself, he’s fighting for his pack. And because he has a pack, he’s stronger. Scott then gets the power to knock Peter out and win the fight.
At the end Kira gets her first tail, which her father made into a throwing star out of the obsidian she used to heal herself. Of course, Coach is, understandably, mad at Scott, Stiles, and Liam, but tells the two older players they need to keep an eye on Liam. Scott doesn’t seem to have a problem with that at all. Lydia gives Parrish the bestiary, which they’ve made into a book, and tells him that she wants to help him figure out what he is.
But the final shot of the finale was absolute gold, Peter gets locked up in Eichen House, drugged with yellow wolfsbane and is surrounded by walls made of mountain ash. Oh, and he’s got a roommate, none other than Dr. Valack, the man with the third eye.
Did you enjoy the season finale of Teen Wolf?