After a year of heartbreak and loss, the only thing keeping Constance afloat is the dog rescue she works at with her sister, Sunny. Desperate for a change, Constance impulsively joins a new gym, even though it seems impossibly hard, and despite the gym's prickly owner.

Rhett Santos keeps his gym as a refuge for his former-military brothers and to sweat out his own issues. He's ready to let the funny redhead join, but unprepared for the way she wiggles past his hard-won defenses.

When their dog rescue is threatened, the sisters fight to protect it. And they need all the help they can get. As Rhett and Constance slowly open up to each other, they'll find that no one is past rescuing; what they need is the right person--or dog--to save them.