While attending a Swiss school for diplomats' daughters, the teenage daughter of the American ambassador uses her access to various embassies to engage in espionage.

Military investigator Colonel Edwards is assigned a case involving Major Cargill, a Korean War POW who is accused of treason. Although Cargill admits his guilt and Edwards' superiors are impatiently pushing Edwards to move the case to court martial, Edwards becomes convinced of Cargill's innocence.