The popular Moravanka brass band performs at the fair. Vasek Pivoňka, the bandleader of the local brass band Kulatěnky, which broke up, decides to put the band back together. The village musicians are sceptical at first, but later they start rehearsing with vigour. Standa, a Prague resident who is working in a pig farm to cure his nerves, helps them to organise the concert. He really likes Evica Kocourková, but her father keeps an eye on her. Young Šišák tries to charm the teacher Olina. Before the performance can begin, the band must succeed before the cultural committee. However, they fail to do so. The disappointed musicians play for themselves at the station and suddenly they are successful. Standa comes up with an idea how to push Kulatěnka through without the permission of the commission. A concert of Moravanka is being prepared in nearby Nechvalin.

The detective case of Captain Jakubec and his colleague Lieutenant Michalek takes place in a small town where the auditor Burian dies after drinking a health syrup. The doctor concludes that it was a heart attack. However, the exhumation of the corpse confirms the suspicion that Burian was poisoned. The auditor's young wife and her lover are the primary suspects. Other candidates for the role of the perpetrator include the manager of the café Orlovský, who asked Burian to destroy the falsified statements in exchange for a bribe, and the managers of two stores where the shortage was discovered. However, the network of suspects continues to expand...