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. But Savannah is bound for Indonesia with or without his protection, and he can't just walk away. When her plan goes horribly wrong, they are trapped in the forsaken jungle of a hostile country, stalked by a lethal enemy. As time is running out, they scramble to escape, risking both their lives to stop a nightmare from spinning even further out of control...