Gary Johnson (Glen Powell) is a philosophy professor by day, lecturing his students on theories of morality. In his downtime he works with the police in surveillance vans as a tech-savvy staff investigator during undercover sting operations. When the temperamental officer who normally plays the role of hitman is placed on leave for misconduct, milquetoast Gary is asked to step in because he vaguely resembles the ousted officer. To everyone’s surprise, Gary thrives impersonating the fabricated killers.