A West German businessman Friedrich Schmidt is arriving to Czechoslovakia with private mission and mission for Intelligence service. He wants to settle the old event from the time of the Second World War when he as a student of the Czech grammar school in the town of Kostelec took part at the denunciation of his schoolmate Pavel Richter. Pavel was during the period of Nazi terror following the assassination of Acting Reich Protector of Bohemia and Moravia Heydrich executed. Schmidt has also to enter into relations with persons suitable for cooperation with the West Intelligence service. Schmidt - earlier, before the German occupation Smíd - meets the schoolmates and endeavors to avert suspicion that arose already at the time of the tragic event.
Inspector Brumpby (Jaroslav Marvan) and the young crime reporter Allan Pinkerton (Vít Olmer) attend wedding of Sir Hannibal Morris (Oldrich Nový) with beautiful Clarence (Kveta Fialová). After the ceremony, Clarence's ex-husband, criminal Manuel Diaz (Waldemar Matuska), who was believed dead, shows up in her room. He wants to get his hands on Clarence and, most importantly, on the money she would inherit in the eventuality of her new husband's death. Diaz makes attempts on Hannibal's life. He knows his way about an underground labyrinth in the château and the traps he sets up for Hannibal seem to work, since Hannibal is apparently found dead after an explosion in the labyrinth, after which his body vanishes. The inspector tries to solve the countless mysteries. In this, he is joined by Allan, always ahead of the man of the law in his estimation and judgment of the situation.
