Archaeologist-spy Tamara Hoylandon has another job for Department E, that supersecret intelligence agency (No Man's Island, etc.). This time out, she's to watch over Dr. Janet McMillan, a top medical researcher whose recent discovery could be a health boon--or a lethal weapon. Tamara joins the pricey Egyptian tour that Janet has impulsively booked--mostly with the aim of harassing her ex-lover Timothy Snipe, a self-proclaimed poet, and his new mistress, Vanessa Papillon, who hosts a popular TV talk show. With elitist antiques-dealer John Benson, his sister Ann, businessman Hugo Bloom, and courier Max Solomon, they make up a splinter group going to Qasr Samaan, an island in Lake Nasser, where they'll be guests of famed archaeologist-lecturer Giles Needham. But discomfort turns to discomfiture, then dismay, as the breakdown of their boat delays the return trip to Abu Simbel. Two members of the party die in this short time--while Tamara tries to decide whether murder's been done and whether young Polly, an aide to Needham, is really Princess Mary of the British royal family, whose disappearance has been widely publicized. Tamara gets to use some James Bondish tricks in rescuing her charge--with a windup that's ironic but flabbily motivated. Told in uneasy flashbacks, this one's a splendid travelogue and never less than entertaining, but it lacks the pacing, tension, and clarity of the author's best work.