Evelyn is a witch with a perfect storm of impulses: terrible taste in bed partners, sticky fingers, and a lust for danger. After she steals from her vampire ex and falls through a portal to another realm, she's fished out of the waters by a band of seafarers and their telekinetic captain. She's immediately given a choice-join their ship's crew or die.

Bowen has no memory of his life before he became one of the Cwn Annwn. He and his band of pirates are bound by vow to patrol through Threshold, the magical sea in between realms, keeping the portals to other worlds safe. When he rescues Evelyn, he doesn't expect to be attracted to the unflappably brassy pickpocket. The longer he spends in her presence, the more he begins to question if his heart is the next thing she'll steal.

But as tension heats up between Bowen and Evelyn, the danger at sea escalates as well. Because Evelyn has no intention of keeping her vows to the Cwn Annwn, and if she betrays the crew, both she and Bowen will pay the ultimate price....