The fishermen Österman and Sjöberg are sued by merchant Wikström. In order to raise capital, they decide to start producing a medicine from a recipe by Österman's father.

The sisters Britta and Ellinor live with their grandfather, music professor Libergius, teacher and leader of the city's orchestra association. In the city there is also a youthful jazz band - to the professor's horror.

The meticulous Fabin Bom is called up for military service in the airforce.