US ambassadors are being murdered. Authorities know they are being poisoned, but they don't know who is doing it. The deputy director of the CIA calls in his best investigator. Blake Parker is a veteran investigator. She has solved murders all over the world, but this is different, mysterious. No signature MO, and no one is claiming responsibility. She recruits an old friend who might be able to help. Is she good enough? Will she solve it before the next ambassador dies? Find out in Ambassador Number Five.