Killer Instinct

S2, E1: While investigating a series of bizarre murders, Nick discovers that an ancient evil from his past is behind the crimes. LaCroix, his former vampire master, has returned to the city in search of Nick, his one-time pupil. The murders, coldly orchestrated by LaCroix, threaten to uncover Nick's sinister secret when he is arrested as the prime suspect. With the help of his partner, Don Schanke, and department pathologist Natalie Lambert, the only mortal who knows his true identity, Knight escapes. Now an outlaw, he must track down the killer and find LaCroix before he is forced to give up his dream of regaining his mortality.