Ever since Bo found Dyson with another woman, she's been inconsolable. Little does she know that, across town at the police station, Dyson's handling heartbreak his own way, and his frustration at having to let go of Bo for the sake of the Light Fae is taking its toll. His violent outbursts at work have landed him in the psychiatrist's office, but he refuses to admit, even to himself, that he wants to be with Bo.
Kenzi drags Bo out of her funk and into a bar for some rebound action and sure enough, a tall-dark-and-handsome Fae named Samir tells Bo that his wife wants the three of them to...get to know each other. And since his wife, Olivia, is a Fury, she gets whatever she wants. Bo initially refuses, being gun shy, but when Dyson walks in, she decides to show him what's up. Bo escorts Samir and Olivia back to her place. Kenzi dons her earplugs.
The next day, Bo gets a surprise visit from Olivia, but it's not about love - it's about revenge. Apparently, Samir has been sneaking around with a human, a girl named Jenny, and Olivia has a stack of love letters from the girl. Olivia tries to hire Bo to kill Jenny - Olivia would do it herself, if not for the rules the Light Fae have laid down about killing humans - but Bo refuses.
Olivia, left without recourse, goes to do the job herself, and Bo and Kenzi rush to Jenny's house to prevent a murder. When they get there, Olivia already has the girl in her grips. Bo manages to kick the Fae off the girl, but Olivia turns her Fury power on Bo. As she peers into Bo's eyes, Olivia's eyes burn red, infecting Bo's mind with rage and madness. Bo manages to grab a barrier that flips the beam back into Olivia's eyes, and Oliva, herself, goes mad. She runs from the place in a fit of insanity as Kenzi and Bo usher Jenny to their house.
Bo goes to Samir's house to get the real story, but she's too late - Olivia staggers out, her hands bloody, and Bo finds Samir with his head lopped off. She goes to tell Jenny, and when the girl breaks down, Bo gives her a touch of good energy to soothe the pain. But it may be too much - Jenny develops a full-on crush for Bo.
Dyson finds out about the beheading, but Bo tells him and The Ash that she only stopped Olivia from killing Jenny. At that moment, Olivia spurts out that it was Jenny, not she, who killed her husband. Bo rushes home to find a note from Kenzi saying if Bo wants her back, she'll have to come to a meeting point to get her. On the bed beside the note: Samir's head.
At the outskirts of town, Bo finds Kenzi bound to a chair and Jenny holding a detonator to a homemade bomb big enough to blow the whole building to bits. Samir isn't the only lover Jenny has killed - there's a closet full of skulls from people who have gotten tangled up with her. Bo speaks sweetly to Jenny and starts approaching, but just before she's close enough to touch Jenny, Olivia's sisters - also Furies - arrive, seeking vengeance for their sister's madness and death. Bo fights them off and grabs Kenzi, and the two flee the scene as Jenny reaches for the detonator and blasts the building, with herself and the Furies, sky-high. Dyson rolls up just in time to see the blaze, and Bo describes the gory scene.
Later at the bar, Bo thanks Dyson for covering for her for The Ash, and Dyson thanks her for wrapping up a serial killer case that had been open for far too long. Bo decides to move past the awkward phase and invite Dyson into a "friends-with-benefits" set-up, which he can't help but accept. And later that week, he's finally open up to his therapist about what's eating at him: His desire to be with Bo.