A radio reporter from Helsinki arrives in the village of Kankkula just before Midsummer to conduct interviews. The old sheriff demands that his nephew Lauri, who serves as the village policeman, continue the generations-old tradition of arresting the old master of Tippavaara, whom the sheriff believes to be brewing moonshine. However, Lauri is in love with the old man's niece Leena, and the couple's plans to get engaged conflict with Lauri's duties.