Out of Control by Suzanne Brockmann

Savannah von Hopf has no choice. To save her uncle's life, she goes in search of Ken "WildCard" Karmody, a guy she barely knew in college who is now a military operative. She must convince him to help her deliver a cache of ransom money into the hands of terrorists halfway around the world. What she doesn't expect is to end up in WildCard's arms before she can even ask for help. WildCard has always had a soft spot for beautiful women. But when he discovers Savannah's hidden agenda, he is determined to end the affair.