Bo and Dyson are figuring out a way to be friends, and what are friends for if not to lend a hand by darting into Dark Fae territory to look for something called a Mongolian Death Worm? The request comes from an old friend of Dyson's, actually, a man named Cayden, who, centuries ago, was Dyson's comrade-in-arms. Cayden comes to tell Dyson that not only has the king they once served died, freeing Cayden from his service, but Queen Chiara, whom the king married after killing her husband, has committed suicide. Chiara was a dear friend, and the news saddens Dyson.
Bo agrees to find the worm, just to keep such a weapon from getting into the wrong hands, but Cumberbatch, the Dark Fae black market arms dealer she approaches, is a dead end. He senses Bo's ulterior motive and traps her, but Cayden comes to the rescue, not only getting her out of the warehouse alive, but helping her heal once they get back home. Bo's not worried about the hint of jealousy in Dyson's eyes - it's overshadowed by her concern for Lauren, who has been staying with them. She's on the lam from Lachlyn and his new policy that all humans must be locked in their quarters when not working.
Posing as well-to-do Dark Fae, Bo and her company attend an underground arms auction and outbid everyone on the Worm. The auctioneer demands the $155 million Bo bid for the worm, but when Dyson explains that they claim the weapon - actually a little old lady glued to her mini television - in the name of The Ash, the auctioneer grabs the television from the woman, thus activating her destructive powers. As long as he holds the TV, he's in charge of her, and just as he's about to direct the Worm to liquefy Bo, Dyson, and Hale with her fiery gaze, Cayden appears, snatches the TV, and kills the auctioneer. He is now in control of the worm, and in a moment, Dyson realizes that this whole escapade has been an attempt for Cayden to recover goods he originally stole. He takes the Worm and leaves the premises.
On a hunch, Bo suggests that they find Cumberbatch, and sure enough, there's Cayden. Infuriated that Cayden put everyone's lives at risk and betrayed his trust, Dyson lunges at Cayden, knocking the TV from his hands. Untethered, the worm blasts the Cumberbatch to bits as Dyson and Cayden continue to brawl and Bo locates the TV, neutralizing the worm once again. Cayden manages to escape, but Dyson easily tracks his blood trail to a van, where the man lies, panting for his life. A loud knock comes from the back of a van, and Bo opens the doors to see a bound woman whom Dyson identifies with a shout and a warm embrace as Chiara. Bo cuts through her ropes, but Cayden has gone missing again.
Dyson takes Chiara home, where her feelings for him overtake her, and the two fall into bed in a passionate embrace. Back at her own home, Bo lays blankets for herself on the couch, insisting that Lauren take the bed. Lauren will have none of it, and though the sexual tension between the two is palpable, Lauren is too shaken and shy to follow through.