The term is Agency jargon for a voluntary defector (a.k.a. a Mickey). The Agency in question is US Armed Services Counterintelligence; Don Halpern is its resident trouble-shooter. Coming over is Colonel Li Yu-hsiang, an Air Attache at the Washington embassy of the People's Republic of China with partial knowledge of a sleeper agent high up in the State Dept. Li's debriefing gets underway in a not-so-safe house in Pensacola, the Chinese Premier threatens to cancel his impending state visit, and you know what's coming so walk on by.