Kai had just about given up on love — until he met sexy merman Tyler and Tyler's wife Zoe. The three heat Kai's hot tub to scorching together, but now Kai's seen something he wants and he plans to have it. He doesn't want another fleeting relationship. He wants Tyler and Zoe. For keeps.

Zoe's not sure she can commit to two men, but when danger threatens the underwater archaeological excavation she's working on, she needs them both to protect. Zoe and Tyler's oldest enemy has returned. They've always run from him, but now it's time to turn and fight.

But Tyler's going to have to trust Kai to protect the love of his life. Can he?