All it takes is one mistake to be marked. One bite to cross a line...into forever.

Diana Hambre is a leopardess shifter. During her heat cycle, she's alone—a widow without a mate. To survive in a volatile world where preternatural races among humans must be in control at all times, Diana cannot let her leopardess nature run wild.

Her senses reel when Shawn Barclay, her boss, walks into her reserved room at the Downtown Den, a private club for shapeshifters.

For an alpha leopard shifter like Shawn, Diana’s pheromone-laced scent is too hard to resist.

Are they willing to cross the line to give in to their primal instincts?

For a night, they agree to quench their carnal desire. Yet, as the moon rises toward midnight, Shawn and Diana learn the difference between hooking up and bonding.

Shawn convinces Diana to let him teach her how to harness her untamed cravings. He uses every method available in and out of the bedroom only to discover he's found the perfect mate and risks losing his heart.