Major Hariev, a State Security officer, manages to learn that the spying center codenamed Citadel receives encoded letters. Sometime later, the Bulgarian agent in the West reports that the spy h as a subscription to the French woman's magazine. The State Security men find a beautician, who received the magazine and delivers it to Ivan Bolyarski, director of an important state department. Hariev follows Bolyarski to his meeting with the Hawk, his associate working in a military unit. The Hawk agr...