In Episode 3 of "The Witch and the Beast," the investigation into the brutal serial murders in Hayden intensifies, delving deeper into the dark world of witchcraft and magic. Kiera Haines, the detective mage, teams up with Guideau and Ashaff to disprove the police's suspicion that the grotesque murders and cryptic messages at the crime scenes are the work of a witch who has turned the cruel acts into a macabre game.

The trail leads to a bookstore, where Kiera identifies quotes from a specific book linked to the crimes, only to find the shop owner dead—a victim of magical violence, confirming the fear that a witch is behind it all. Kiera's despair hints at a personal curse, as she believes harm is coming to those close to her.

The plot thickens as Kiera rushes to another crime scene, while Guideau and Ashaff face a mysterious attack at their hotel, revealing the witch's interest in Kiera. The duo confronts Kiera with the suspicion that she is the witch's target, prompting her to recount the tragic beginnings of the murders—her friend killed and her family attacked—suggesting a deeply personal vendetta.

The episode ends with Guideau and Ashaff leaving Hayden, taking the dangerous grimoires with them.