Dana Mentink 
Escape From the Badlands [EPUB ebook] 

After his brother is convicted of murder, Shane Mason will do anything to clear his name. But when his investigations lead him to enter South Dakota's Desert Quest extreme race, Shane is floored by the surprise waiting for him. Kelly Cloudman—the woman he can't let himself love—is the race's medic…and the killer's next target. A painful memory from his past divided Shane from Kelly, but he's not going to let her out of his sight again. Even if it means revealing his secrets, Shane won't stop until he's found the truth—and kept the murderer from striking again.