Shadow Game (GhostWalkers, Book 1)

Shadow Game - Christine Feehan The first book in this series. A group of soldiers have been experimented on in order to make them psionic and to work as a team. The leader is Ryland Miller and he's worried that they're not happy with the results, some of his team have disappeared and he wonders if he's next. Lily Whitney is the daughter of Peter Whitney, the man who is responsible for these experiments but when he dies she discovers some truths about her past that are difficult. Staying alive is the biggest thing. The two characters find themselves very attracted to each other.