At Bo's Dawning ceremony, Trick paints a sacred symbol on Bo's forehead to symbolize the portal through which she will cross. As she prepares to step through the metaphysical portal into the temple of the Dawning, Dyson arrives and offers himself as Hand, and even though Bo has no idea what this means, she's against it. Dyson prevails, however, and the two enter the other realm, where a sketchy character who calls himself the Caretaker tells Bo she can leave as soon as she has the key in hand.
Dyson grins and runs toward the sound of growling, leads them straight into a battle with a gnarly monster, and dives between the creature and Bo. The ghoul disappears and Bo asks Dyson what's up with the hero stuff. His reply is his long-overdue declaration of love, which she responds to with a kiss, then a punch.
The gnarly guy reappears, dangling a key, which Bo grabs and then disappears. Dyson roars to the Caretaker to tell him where she is, but he cryptically offers Dyson a life inside the temple in which all his dreams can come true.
In what apears to be an alternate reality, Bo is now a cop, and her partner, Lauren, is clearly still hung up on her, following their breakup. Bo goes to question her asset, McKenzie, a black-haired waif who's terrified that if she testifies against "the family", they'll kill her for being an outsider. Bo promises to protect her, but her chief, Trick, says there's nothing they can do for her. Bo drives to her home where her neighbor, Tamsin, greets her with bloody hands and says it's a good time for a "wander". In the house, Bo's husband, Dyson, is waiting in his doctor's scrubs with a loving embrace.
Bo feels weak and goes to get a drink of water, and on her way finds herself in a dark room in evening where her father is singing to her infant self. The man leaves the baby under the care of a nurse, whose throat is then slit by Aife, who steals Bo and disappears.
Bo turns and is back in her bedroom, telling Dyson that she's pregnant. They're wildly happy until Bo doubles over in pain, clutching her stomach. Dyson breaks his role and tells her that it's not a baby, but her cells devolving, and curses the Caretaker, who told him that this illusion wouldn't hurt Bo. They realize that the Caretakers words – key in hand – refer to the Hand (Dyson) being the key, meaning that Bo must kill Dyson in order to leave. He begs her to do it and she refuses until he lunges for her, meaning to rip the "baby" out of her body, when she instinctively stabs him. He lies bleeding as a portal to the real world opens and the Caretaker urges Bo to leave. She's hysterical at the thought of leaving without Dyson, and realizes that there is another way out: on the floor, with Dyson's blood, she draws the same symbol that Trick drew on her forehead. If the Hand is the key, she can use it on any door, and she transports herself and the wolf out of the temple.
But in back in their accustomed reality, Dyson is still dead. Bo crouches, sobbing, over his body, until a terrible light possesses her, causing her to stand, draw the chi out of Trick, Stella, Lauren and Kenzi, and, in a foreign voice, speak of ruling the land with her father. She then breathes the chi into Dyson and brings him back to life, and Lauren watches Bo's reunion with Dyson with a sinking heart.
Bo then enjoys a much-deserved drink with Kenzi while Stella invites Trick to come with her to her next assignment in Scotland. His feelings for Stella are strong, but he must stay with his granddaughter to assure her safety. And when he reads a divining instrument foretelling of the arrival of The Wanderer, he is certain that this was not only the right choice, but the only one.