Scott is captured by the assassin in this Teen Wolf scene. It is from the episode "Perishable."
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Liam makes a discovery in this scene from Teen Wolf: there are supernatural forces at work.
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Scott and Derek are targeted by an assassin at the lacrosse team's bonfire on Teen Wolf. "Perishable" is the ninth episode of the show's fourth season.
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Teen Wolf Season 4 Episode 9 Quotes

Parrish: Just tell me one thing. Are all of you like Lydia? Are you all psychic?
Derek: Psychic?
Parrish: Yeah.
Scott: Not exactly.
Parrish: OK then, what are you?
[Scott replies with blazing red eyes.]

Parrish: I was set on fire. All of me should be gone.
Scott: Not if you're like us.
Parrish: Like you?
Derek: I don't think he's like us.
Lydia: Then what is he?
Derek: I'm sorry, but I have no idea.