Rising by Claire Cullen

A lone wolf. A lonely merman. And a place to call home, if they can get there.

Kicked out of his pack as a kid, Jace has always considered himself a solitary wolf. He’s happy to help the Eden pack rescue wolves and other shifters, but he’s not ready to give up his life as a thief. Until he breaks into a mansion to steal a priceless watch and finds something far more intriguing—a merman.
Robin has lost everything that matters to him. Trapped in an opulent prison with his would-be savior, he can’t see a way out. And then one night, a wolf appears. But this wolf is far more than he seems, and Robin is thrown headfirst into a world he never dreamed existed. A world that he and Jace could be a part of. But first, they have some kids to save.