Marta Hornová, a blind soloist of the radio orchestra, becomes acquainted with the actor of the state drama Robert Holan. He also meets her sister Helena, a talented sculptor, whom he mistakes for Marta. However, when he returns her blue veil, which she supposedly lost during their meeting in the radio building, Helena realizes that Holan actually loves her sister...
Young engineer Petr Pavelec works on a dam plan on the Loučnica River. He meets Irena, the daughter of an unscrupulous construction entrepreneur Berka, and falls in love with her. When Petr's project wins the tender, Berka and Irena take him on as a partner, and the company is awarded the contract to build the dam. Petr, in love, does not see how sloppy the construction is being carried out. He only sees it when a worker is killed on the construction site...
More than twenty years after the Second World War, a mining engineer named Fischer is revealed as a former member of the Gestapo, Karel Kraus. He is sentenced for murder to eight years in prison and now works with other prisoners on the renovation of the Convent of St Agnes of Bohemia in Prague. Then a car with a foreign registration begins to park regularly close to the construction site. Its crew, a man and a woman, contact the construction foreman, who probably would not reject a bribe offer to perform some service. The prisoner Bicík is appointed to work with Kraus; Bicík gives him a message from Kraus' brother Bert, who lives abroad, that he wants to help him escape.
