When a local high school student goes missing, it is feared that a serial killer has returned after more than a five-year absence.

While questions arise as to whether Gretchen was killed by the Russian River Killer (RRK), both Detective Mike Serrato and Canaan High School guidance counselor Leo Doyle struggle to hide their guilt.

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

Mike and Cyd learn about a missing person from 26 years ago: Beth Stanley, Arlen Doyle's wife and Leo's mother, just as another near victim is discovered holding Mike' business card in her hand.

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

Struggling to keep his demons in check, Leo is tested at every turn, while the true identity of Gretchen's killer is revealed.

A stay in the hospital introduces the RRK to his next victim, while Cyd shoots Gretchen's killer in a standoff.

Beth Stanleys remains are found, Arlen is charged with her murder, and a victim's body goes missing.

Leo receives an offer from a neighbor that would free him from his past transgressions, while Paxton and Sam discover a shrine to the murderer's work.

With another taking the fall, the RRK believes he has gotten away with murder, until Mike goes beyond the call of duty to figure out his true identity.