Hansen is a double agent working for the East German secret police. He has infiltrated the American Military Intelligence Division, part of a network planning to invade the GDR. Hansen's mission is to obtain and bring back classified, top-secret documents. After the cover of several US spies is blown, Hansen's boss suspects a leak in his own ranks and has Hansen take a lie detector test. This first East German spy thriller was a great hit with East German audiences. It was loosely based on real events from 1956, but the allegation of a Western plot to attack the GDR was fabricated-- in part to justify having built the Berlin Wall.