A woman is missing (a killer? or just afraid of being killed?) who is not only a member of a hot money operation but is also the carrier of a smallpox epidemic to England, where her associate and plane sealmate has come down with it. Dr. Gregson of the public health service tries and fails to put a cordon sanitairc around the outbreak and has additional personal agonies his wife, using herself to test a new scrum; his son abducted by the enemy. . . . All with the appropriate virulence and urgency.