Bo is trying to clean Dyson out of her heart by cleaning her home, which makes Kenzi very unhappy. She heads to the Dal for beer and sympathy, where Trick introduces her to a Brownie - a cleaning Fae, whom Kenzi happily takes home.
Bo, meanwhile, heads to an apartment complex where all of the residents seem to have lost their minds, but Frank, a Light Fae working as the doorman, believes a Dark Fae is preying on his wards. Frank says The Ash refused to do anything, so Bo agrees to find out what she can. She helps Lauren investigate the building, and with Dyson out of the way, things get hotter between the two. Bo goes home for a well-deserved rest, but is woken in the middle of the night by a surprise visit from Dyson. He tells her he wants to be with her and wraps her in a sultry embrace, just before he reaches into her chest and pulls out her heart.
Kenzi hears Bo screaming in her sleep and comes running, only to find a black-robed woman riding Bo and torturing her. The woman turns into mist as soon as she sees Kenzi, but Bo feels as though the woman planted hooks in her mind. She goes to Lauren with this new information, and Lauren runs tests on Bo to see what kind of Mare - as in, nightmare - could be tormenting Bo and the human residents. As Lauren works, the new Ash bursts in and declares that Lauren is his property, and Bo must make a formal request if she wants to "borrow" Lauren.
Bo is furious, but since she hasn't slept for days in an attempt to keep the psychological horrors at bay, she needs the help of The Ash. He spurns her, and adds that no one named Frank came to see him. She's furious at being lied to, and dangerously tired, but she seeks vengeance on Frank. Kenzi has heard of a Fae called a Baku that eats bad dreams, and employs her Brownie to search for the elusive creature as his final task for her. But she may be too late, since Frank, truly a Dark Fae and Sandman, has put Bo into a very deep sleep so that his wife, the Nightmare, can feed on her - his whole reason for contacting her.
Bo manages to shake off the sleep and escape the Sandman's lair, but she feels herself pulled by an unknown force to the basement of Frank's building. She's still under the Sandman's spell, awake yet dreaming, as she sees her hand open a door, and behind it, she sees herself as an old woman, who sucks Bo's life force out of her. Just then, Kenzi arrives with the Baku, who is able to free Bo from that dream, but Bo must break the Mare's deeper psychic link on her own.
In Bo's mind, Dyson appears with the same offer of love as before, but this time, Bo stabs him in the side and walks away, freeing herself of the Mare, and possibly her attachment to a relationship that can never be.
Bo has one more job before she rests - to tell The Ash that a Dark Fae was feeding in his territory. When he counters with an offer that she freelance for the Light in exchange for protection without bondage, she tells him that she plays by her rules, and hers alone.
Tamsin tries to do the job she's assigned to do, but Bo has a hold on her stronger than The Wanderer.
Hale slips Kenzi a sacred charm that will keep her safe in the trouble to come, and tells her something that will change their relationship forever.