When local high-schooler Gretchen McGrath goes missing, Detective Mike Serrato fears that a serial killer who terrorized his town five years earlier is on the prowl once again.

Mike launches right back into his old investigation when Gretchen is found dead and all the clues point to the RRK: the Russian River Killer.

A man from Mike's troubled past resurfaces and Leo reveals more of himself to a student than he's comfortable with.

Just as another near victim is discovered, Mike and Cyd learn about a missing person from 26 years ago.

A father and son hunting trip takes an interesting turn, while further doubts are cast over whether Gretchen was an RRK victim.

The RRK meets his next victim, while Cyd faces a tense standoff.

A victim's body goes missing.

Leo receives an interesting offer from a neighbour. Meanwhile, Paxton and Sam discover a shrine to the murderer's work.

The RRK seems to have gotten away with murder - will the killer's true identity be revealed before it's too late?