Deaton helps Scott clean out the wounds he got from the fight with Derek in the last episode. There’s a dead man lying on the table with claw wounds raked down his body. Deaton tells Scott about a book sounding like a supernatural encyclopedia before Chris Argent, Gerard Argent, and another hunter walk into the vet’s office. Scott is hidden away in a closet as Deaton explains his theory about how the man was killed. Some monster paralyzed the man with venom to the neck before killing him with his claws. Deaton says he has no clue what killed him, but gives some characteristics, stating that the hunters should “be afraid, very afraid.”
Stiles is at Armor Tire where he argues with the mechanic, Tucker Cornish. All he needed was a starter, but the mechanic tells him he needs a lot more work done. Originally he tells him $1200, then ups it to $1500 when Stiles argues. Stiles storms off and gets his hand covered in a mysterious slime as he opens the door, and within seconds he loses motor control in his hand. At that point he notices claws on one of the lifts and tries to yell out, but he cannot be heard and the monster appears, cutting the mechanic in the back of the neck with its tail. 204image3-medium-17909Stiles falls to the ground as the venom moves throughout his veins and the monster triggers the lift with Stiles’s Jeep on it. Stiles struggles to get to his phone and dial nine one one as the lift continues until it eventually traps the mechanic under it, killing it. The monster appears and roars at Stiles before disappearing.
Allison checks her window to see that Scott wants to meet up at nine o’clock. Just as she’s about to leave Gerard shows up, wanting to know what she’s doing. Gerard forces her to stay and talk to him, and Scott is shown at the meet up point, waiting as nine o’clock comes and goes. Gerard drops a book and Allison picks it up for him before taking his pills. He uses this as a segue to talk about trust. She insists that Gerard can trust her.
Stiles is giving his father the edited version of the story of what happened at the mechanic’s shop as the emergency services clean up and seal the scene. The Sheriff is convinced that Stiles isn’t telling him something, but Stiles holds his ground.
Allison arrives at the lookout rock late and sees a message from Scott saying that he couldn’t wait and he missed her. Scott has left to pick up Stiles from the mechanic’s shop since his Jeep is being detained by the police department as evidence. Stiles tells Scott that the monster seemed reptilian, not like werewolves, and that it seemed to recognize Stiles.
Isaac, Erica, and Derek are training. Although the gymnastics are pretty, both Isaac and Erica continually get slammed into the ground by Derek, who isn’t impressed with them by any means. Boyd watches with concern. Frustrated, Derek asks if any of them will do anything that isn’t completely predictable and Erica gets up and kisses him aggressively in response. Derek plays along for a few seconds before throwing her to the ground. Isaac whines about needing to heal and Derek turns snaps his forearm knowing that it will heal eventually before launching into a speech about how the betas need to learn everything he knows ASAP with new threats in Beacon Hills.
Lydia’s mom walks into Lydia’s bedroom to wake her up and pulls up the covers which are soaked in blood. Her mother is worried and asks what happened, but Lydia doesn’t seem to know. The mirror is also shattered. Lydia is sitting outside the counselor’s office with an unfamiliar boy who asks here about why she’s there. She gives him a snarky response, which he responds to by calling her cute.
Stiles and Scott sit on the stairs where Stiles is delivering a message from Allison that she’s super sorry about missing him, and loves him, and is coming to the game. Scott tells Stiles about the supernatural encyclopedia that Deaton mentioned, and Stiles gives it a name, the bestiary.
In the counselor’s office, Lydia asks what qualifies Ms. Morell to be a guidance counselor when she’s a French teacher who isn’t even French, and Morell responds that she has a Masters in Behavioral Psychology and she’s done over three hundred hours of field work. Lydia responds with, “C’est pas bien” which roughly translates to “That’s not good enough.” Morell asks why she’s even there if she’s fine, and Lydia says she’s only there to appease her parents. We see the mysterious boy from before watching her from the hall. They also talk about her friends before the session closes. Lydia comes up with the phrase "Because the ones closest to you can also be the ones holding you back the most," although she doesn't know where she heard it.
In the locker room Jackson asks Danny about boosting the quality on his video, and makes him promise to keep it to himself. Danny is confused about about the whole situation, but Jackson leaves before he can ask any real questions.
Stiles is talking to Allison about the bestiary, which she also wants to call the bestiality. She knows about the book, and her and Scott send Stiles back and forth delivering messages regarding it. The conversation ends with Allison saying that she needs her grandfather’s keys to get the bestiary out of his office. Gerard is seen with Allison putting said keys in his coat pocket as they talk about the lacrosse game happening that night. They leave the office at 6:45 for the game.
At the game, Danny walks up with Matt, presumably to talk about the video. Jackson is angry that Danny got Matt involved after specifically being told to keep it to himself. Danny and Matt explain that two hours of footage are missing from the tape like they’ve been edited out. During the game Beacon Hills is losing gravely. Stiles sits on the sidelines in a track suit while Scott and Jackson bicker over their performance that night on the field. Scott says hat he can’t use his supernatural abilities on the field with Gerard watching. Gerard gives Allison his coat because she’s cold, and she realizes that the keys are in the pocket. Allison subtly passes the keys to Stiles. Matt is talking to Melissa McCall about his photos. Matt says that he takes pictures of “anything that catches his eye” while looking at a photo of Allison. Stiles sees Lydia in the car crying, and after weighing his options for a moment goes to talk to her. He convinces Lydia to talk to him. The coach puts Danny back on the field even though he’s clearly too injured to be on the field. He still needs one more player, so he pulls Boyd out of the stands. Erica warns him that Derek wouldn’t like it, but Boyd ignores the warning.
Lydia starts to open up to Stiles, but hearing the game makes Stiles remember that he has to go get the bestiary quickly before the games ends. He asks Lydia to give him just five minutes and she’s annoyed, but agrees to wait reluctantly. Stiles sprints into the school and goes through Gerard’s office, unable to find the bestiary. Erica walks into the office and the scene cuts back to the Lacrosse game. One of the players who’s been plowing BH athletes for the entire game charges at Boyd but Boyd holds him off. His eyes go yellow as the crowd cheers.
Erica brings Stiles to Derek, who’s at the pool. Derek asks him about what happened at the mechanic’s and Stiles responds with sarcasm. Derek’s response is a thinly veiled threat.
Scott tries to tell Boyd to get off the field because he’s out of control. The player from before mows down Scott, who’s leg clearly was broken, but he’s healed before the Coach and fans reach him. Gerard has a question for Scott.
Stiles begins to tell Derek and Erica about the monster, which shows up as Stiles describes it. Derek immediately goes onto the defensive, and the monster hits him with the paralytic venom. Derek tells him to call Scott, and Stiles loses his balance trying to keep from dropping his phone, which leads to Derek getting thrown into the pool. After a second’s hesitation Stiles dives in after him, knowing that he’s paralyzed and unable to swim.
Gerard and Allison arrive home as Chris and Victoria Argent are finishing up dinner. Gerard apparently insisted that Scott come to dinner with them as well. Dinner is predictably awkward and silent. Gerard forces them into a corner by having them insist that they are fine with each other before asking why they broke up. Stiles and Derek are still barely managing to keep afloat in the pool before the monster shows up. Chris asks Scott to help him get dessert and threatens him before they both very angrily get dessert and bring it back to the dining room. The monster continues to the circle the pool, but apparently it has a problem with water after touching the surface and recoiling.
Scott and Allison retreat upstairs where Allison leads Scott into the room where Gerard’s presumably staying. Allison finds a safe. Scott listens to the lock in order to guess the combination, realizing that when he reaches the right number he’ll hear the click of the lock snapping into place. They find a leather bound book but it’s a cookbook, not a bestiary, and Gerard is seen enjoying the recipe, which was fish.
The monster continues to circle and Derek and Stiles continue to float, although Stiles is clearly getting tired. Stiles sees his phone and Derek guesses what he’s thinking before he even says anything and protests. Derek thinks that Stiles has been holding him for two hours because he thinks Derek will attack the kanima. Stiles is offended that Derek thinks that little of him and lets him go. Stiles starts swimming toward the pool deck as Derek sinks to the bottom of the pool. Stiles gets his phone seconds before the monster and swims far enough back into the pool that he’s safe. He gets ahold of Scott but Scott says he can’t talk and hangs up. Stiles furiously throws his phone into the water and dives back into the water to get Derek.
Allison suddenly realizes where the bestiary is and her and Scott return downstairs. Scott makes his exit saying he needs to pick up his mom and pulls up to the school. He calls Stiles, but Stiles’s phone is at the bottom of the pool. Stiles can’t hold Derek any longer without some support and goes to grab onto a dive block but misses and both him and Derek start to sink before Scott arrives and throws them both out of the pool. Scott and the monster begin to fight. Scott picks up a shard of glass to use as a weapon and the monster is confused by its reflection before running away.
Scott and Stiles find the bestiary and are beginning to look through it when Derek and Erica return with Derek stating that this monster is called a “kanima”, which he figured out when it was confused by its reflection. Derek tries to explain the difference between it and werewolves since they are both shapeshifters, and Stiles supplies that it’s an “abomination”, which Derek agrees with. Scott argues that they all need to be working to gather on this, and Derek makes the ultimatum that he’s going to find it and kill it.
Scott goes to the hospital to pick up his mom but Gerard shows up first and stabs him in the stomach before telling Scott that he better do what Gerard asks or he’s going to hurt Melissa. Melissa shows up and asks if he’s okay, and Scott insists that he’s fine. The episode ends with Scott’s blood dripping onto the camera lens.