Two friends, Szczepko and Tonko, are made unemployed in a toy factory where there was a ban on singing and they broke the rule. In a park they find a abandoned baby, and they take it into their care. Meanwhile, Wanda, owner of a toy shop, comes to Lwów with her uncle. He wants his niece to work for the director of this factory. By coincidence, the child is given to Wanda. Szczepko and Tonko look for him desperately. But the uncle is more and more happy about having the child. After numerous hurdles, the child remains at the uncle's, Wanda and Julian are in heaven, and Szczepko and Tonko, reconciled with fate, leave....

Two apartment house dwellers, although unrelated, share the same name. One is an older man with an appreciation for and love of classical music, while the other is a younger man addicted to swing music. The niece of the older man arrives for a visit and gets into the wrong apartment. Complications arise.