John Cardinal has been demoted for a hunch about a case that he wouldn’t let go. But he is brought back to the Homicide Unit when the body of missing 13-year-old Katie Pine is discovered, proving his instincts correct. As the series unfolds, back on the case, Cardinal’s search for her murderer soon becomes an all-consuming race to stay ahead of a serial killer. Meanwhile, he must manage his own precarious family issues and secrets, and keep a watchful eye on his new partner, Detective Lise Delorme, who he believes may have her own secret agenda.

As Algonquin Bay PD attempts to smooth over the botched investigation into Katie Pine’s disappearance with the community, Det. Lise Delorme (Karine Vanasse) risks exposure of her investigation in an attempt to catch Det. John Cardinal (Billy Campbell) in the act of a crime. Meanwhile, the killer zeroes in on his next victim.

As Eric (Brendan Fletcher) encourages nervous protégé Edie (Allie MacDonald) to torment their drugged and bound captive Keith (Robert Naylor), Delorme (Karine Vanasse) fears Cardinal (Billy Campbell) has sidelined her again – is she being paranoid, or is her partner onto her? Cardinal gets a break in the Curry case that he hopes will lead them to the killer.

Woody Baldwin (Gord Rand), a small-time B&E artist, gets caught in the center of Eric (Brendan Fletcher) and Edie’s (Allie MacDonald) twisted world when he breaks into their basement dungeon and finds Keith (Robert Naylor). Meanwhile, Cardinal (Billy Campbell) and Delorme’s (Karine Vanasse) personal issues threaten their new partnership and Cardinal takes big risks in the investigation that put him at odds with Dyson (Kristen Thomson).

When Woody Baldwin’s (Gord Rand) body is found hastily disposed of, Detectives Cardinal (Billy Campbell) and Delorme (Karine Vanasse) are able to connect it to Eric Fraser (Brendan Fletcher), and Eric to Katie Pine and Todd Curry. They know they’ve got their killer – now it’s a mad dash to find him before he murders Keith (Robert Naylor). Meanwhile, Cardinal meets his daughter Kelly (Alanna Bale) when she makes a surprise trip home to visit her mom.

In the final episode, Cardinal (Billy Campbell) realizes that Eric wasn’t working alone. He saves Keith (Robert Naylor), but may be too late to save his daughter, Kelly (Alanna Bale), from Edie’s (Allie MacDonald) violent revenge. Delorme (Karine Vanasse) finally finds the answers she was looking for about Cardinal’s dark past, and must decide whether to turn him in.