When Amy, a bowling alley worker, encounters a violent demon that only she can see, the self-made demon hunter Raquel comes to her rescue; the pair must become allies when a demon possesses Amy's best friend, Suzanne.

Amy and Raquel must dispose of Suzanne's body; Raquel reunites with a man from her past; Amy and Raquel's exorcism attempt puts them firmly on Callum's radar, and he recruits the powerful, soul-sucking Mercy to take them out.

Amy's best friend, Suzanne, returns from the dead as a bloodsucking revenant; the demon hunters capture Suzanne and look for a remote place to hide as Callum closes in.

Callum uses Suzanne as bait to lure Amy and Raquel into a deadly trap; Amy's rescue attempt results in becoming stuck in an elevator with a bloodthirsty Suzanne.

Raquel sees a new side of Harry when they go on a date, but Amy has a disturbing premonition about him; Amy and Jake get captured while trying to foil a demonic plot, forcing Raquel and Harry to save them.

With Halloween upon them, Amy and Raquel go into hiding, but a close ally betrays them; events spiral dangerously out of control as the gates of hell open.