|“|| "Okay, now put this on."|
"Isn't this one of the heart-rate monitors for the track team?"
"Yeah, I borrowed it."
"Temporarily misappropiated! Coach uses it to monitor his heart-rate with his phone when he jogs, and you're gonna wear it for the rest of the day."
"...Isn't that Coach's phone?"
"That, I stole."
Scott is chased by a werewolf in a parking garage. The werewolf turns out to be Derek, who was testing Scott's skills. Scott asks Derek to teach him how to control his changes and Derek agrees to do so if he stays away from Allison, as she is a distraction. Scott agrees but goes to see Allison anyway. He then has a run-in with the Alpha werewolf, who draws a spiral on his window, similar to the one on Derek's sister, Laura's grave. Scott tells Derek about the spiral, which disturbs Derek. Since Scott's short temper is what sets off his transformation, Stiles decides to help Scott control his anger. They both realize that Allison keeps Scott calm. Jackson, disturbed by the claw marks on his neck, has strange hallucinations. Derek visits his burnt uncle and asks about the Alpha werewolf but leaves after no response. He finds an article about a dead deer with a spiral etched into its fur on his car, learns the town vet dealt with the animal, and visits him. When the vet lies, Derek angrily tries to get the truth from him. Scott stops him just as Derek knocks the vet out. He tells Derek to meet him tonight at school, where he and Stiles sneak in to use the PA system so Scott can call the Alpha werewolf. Derek arrives with the unconscious vet in his car. After Scott calls the Alpha werewolf, the boys go outside, where they notice the vet is gone from Derek's car. Derek is then lifted by the Alpha Werewolf and thrown against the wall, knocking him out. The Alpha then goes after Scott and Stiles, who lock themselves in the school, panicked and unsure if Derek is still alive.
- 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 (credit only)
- Orny Adams as Coach Bobby Finstock
- Jill Wagner as Kate Argent
- Ian Bohen as Peter Hale
- Seth Gilliam as Dr. Alan Deaton
- Adam Fristoe as Adrian Harris
- Desiree Hall as Nurse Jennifer
- Desmond Epps as Senior 1
- Mark Cook as Senior 2
- Hillary Brant as High School Student
- Marvin E. West as Deputy Sheriff (uncredited)
- This episode establishes that the spiral is the symbol of revenge and retribution in the Werewolf culture after the Alpha draws it on the fogged-up window of Scott's mother's car. This is a symbol that will come into play throughout the rest of the series.
- It is also confirmed that a Werewolf's transformation is triggered by an increased heart rate in this episode, which was first implied in Wolf Moon.
- This episode marks the first true hint of Alan Deaton's Druid nature when he manages to escape from the trunk of Derek's Camaro after he was tied up and locked in there by him.
- It is also suggested that Deaton is the Alpha, though this was ultimately proven to be false by the end of the season.
- This episode marks the first mention of The Beast of Gevaudan, or La Béte du Gévaudan, a famous French werewolf who was said to be slayed by a member of the Argent family in the 1800s and is based on a real creature who terrorized France during the same time period. The Beast will become a major plot-line in the second half of Season 5, as will the Argent Family's connection to it.
- Jackson sees Stiles pelting Scott with lacrosse balls to help him learn control over his lycanthropy, continuing his investigation into what is causing Scott's strange behavior that started in Wolf Moon. It is this suspicion of Scott that leads Jackson to start to romance Allison in order to mess with Scott and get closer to what he's hiding.
- Jackson also continues to suffer side effects from being stabbed in the back of the neck with Derek's wolfsbane-coated claws in Magic Bullet, which caused him to hallucinate that a clawed paw was coming out of his throat
- Peter Hale appears in this episode. He was last seen in Magic Bullet, and he showed signs of coming out of his coma when Derek came to visit him in hopes of getting answers about who the Alpha is.
- Stiles forgives Scott for not protecting Sheriff Stilinski from getting bumped by a moving car in The Tell in this episode.
- This episode marks the first of many instances where Derek is wrongly assumed to be dead when the Alpha claws him so badly in the back that he starts to cough up blood. This will continue to be a running joke throughout the next few seasons.
- It is implied that Allison is Scott's anchor in this episode, which will be confirmed later in Season 2.
- The title refers to the heart rate monitor Stiles stole from Coach Finstock to test Scott's pulse in relation to his transformations into his Werewolf form. It is also a double entendre in reference of the fact that Derek spends the episode monitoring Scott's relationship with Allison, as he believes that he needs to break up with her to ensure that the Argents don't find out he's a Werewolf.
- Grocery Store
- Parking Lot
- Argent House
- Allison's Bedroom
- Beacon Hills High School
- Mr. Harris' Classroom
- Lacrosse Field
- Locker Room
- Beacon Hills Memorial Hospital
- Peter's Room
- Beacon Hills Animal Clinic
- Reception Area
- Exam Room