Scott is captured by the assassin in this Teen Wolf scene. It is from the episode "Perishable."
Liam makes a discovery in this scene from Teen Wolf: there are supernatural forces at work.
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.

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.