When a shark attack cripples mermaid Maera, only the shape-shifting sea witch Luka can help. Luka offers a bargain: a brand-new life in a whole new realm IF she can make a god fall in love with her within one month. If Maera fails, she'll turn to sea foam.

Thrust into an unfamiliar world of longhouses, rune magic, and northern lights, Maera charms the handsome Prince Erik despite her inability to speak his language. As Luka's biting criticisms slowly turn into playful banter, Maera starts to suspect that the witch is made more of mischief than maliciousness.

However, the deadline nears and Maera realizes Luka harbors dangerous secrets about this new world and even her true identity: Knowledge that could change the rules of their bargain completely. And not in Maera's favor.