Her Russian Protector (6 Book Series)

From Book 1: Desperate to find her sister, Erin goes to the only man in Houston who can help her--Ivan Markovic. The intimidating, tattooed Russian operates one of the most elite mixed-martial arts training centers in the world but it’s his shadowy past and reputed connections with Houston’s underworld that interest her most.

To find her sister, she’ll need the help of her big, scary Russian protector—but asking for help from a man like Ivan carries a steep price, one that might just include her heart.