Cressida Porter, grad student, finds herself in the middle of a CIA operation in Turkey where she is trying to find a tunnel once explored by T. E. Lawrence (Lawrence of Arabia). The man who promised to be Cressida's interpreter and guide has placed a microchip on her that is supposed to lead Ian Boyd to the leader of a major terrorist cell. Ian's mission is to follow Cressida, but when Ian and Cressida meet, they begin a rollicking adventure through Middle Eastern deserts dodging religious extremists and CIA traitors along the way. This is a good entry in the Evidence series. There is lots of action and adventure as well as romance in this book. Cressida and Ian's early mistrust of each other not only develops great chemistry, but also shows each character's deep determination to do the right thing. Overall a very good read.