Bridge engineer Akseli Jaatinen arrives to stir up the lives of the inhabitants of a small Finnish village. Jaatinen is well-liked at the bridge construction site, but he quickly finds himself clashing against the local decision-makers. The bridge engineer is also popular with the ladies and, being a man of energy, he manages to take care of several of his admirers at once.

Katariina, an orphaned girl from the north, travels to Helsinki to live with her distant relative Mauri, who has been appointed her guardian. The unpretentious child of nature irritates, amuses, and charms Mauri, who is accustomed to high society, and his bachelor friends.

A newly graduated nurse Tuulikki starts a job in a closed ward of a psychiatric hospital. Her innocence is being challenged by both her colleagues and patients. A new patient Katariina has a fire burning deep inside of her.