When Sienna Lane walks in on her boyfriend Jax Deneris in bed with her sister, her world falls apart. In less than five minutes, she’s homeless, friendless, family-less. Vowing to get back at Jax, Sienna quickly charts a course of revenge that will hit him where it hurts most -- in the MMA ring. Step one: convince Jax’s rival, Kayden Williams, to train with her. At first, Kayden wants nothing to do with Sienna’s schemes, but when he figures out that she might be able to give him an advantage, he caves, letting her first into his home, then into his bed, and finally into his heart. But as much as she cares about Kayden, she can’t let her anger go, and it threatens the shaky foundation they’ve built together from their damaged lives. When Kayden gives Sienna an ultimatum -- it’s either him or her revenge, she’s forced to decide. Is getting back at Jax worth throwing her future with Kayden away?