At the Ronov castle, the archive-keeper professor Nykl (Milos Nedbal) is searching for the lost painting The Naked Shepherdess by the famous Fragonard. Nykl is just about to disassemble the mantelpiece in the knight's hall, convinced that the painting must be hidden somewhere inside. His efforts, however, meet the strong disapproval of the castle manager, Anna Juzová (Jirina Petrovická), who knows very well where The Naked Shepherdess is. She wants to get hold of the painting herself, to emigrate and smuggle it along. In fact, Anna deals with forgeries of the most distinguished old masters, selling them abroad. The copies are made for her by the painter and restorer Maudr (Martin Ruzek) and the certificates of authenticity are issued by Anna's companion - expert Laburda (Karel Höger). One day, Anna is found murdered in front of the castle's fireplace.
Basada en la novela de Karel Capek, el destacado escritor checo de principios del siglo XX que acuñó la palabra robot para su obra R.U.R., la historia gira en torno al descubrimiento de Krakatit -un poderoso explosivo- por parte de Prokop, un científico experimental que, tras un explosión accidental en su laboratorio, entra y sale del delirio. Cuando se da cuenta de que, en un período delirante, le ha dado la fórmula para hacer Krakatit a uno de sus colegas, intenta encontrar al hombre, quien no se da cuenta de lo peligroso que es Krakatit. En el proceso, casi vuelve a revelar su descubrimiento a intereses extranjeros, a un grupo de anarquistas y a fuerzas de la oscuridad aún mayores...
After an attack against the guard of the Third Reich, Nazi repression intensifies, and the Czechoslovakian resistance's organized sabotage in an aircraft factory leads to Gestapo shootings.
