Pekka Puupää and Pätkä, who return to Helsinki from an unsuccessful variety show tour, are forced into refresher training, where they are trained as frogmen. During the diving exercises, the friends encounter the mermaid Helmi, whom they help into the bathtub at home, to Justiina's shock. The friends, who have become civilians, eventually end up on a plane bound for Suez, being cornered by UN soldiers.

Max Sjöman, Architect: "This is the story of my daughter. Her life was short. Short is not purposeless. I brick her picture into the cornerstone of an atomic power station. It is my testament to the future generations. They'll see from that photograph what a healthy child once looked like."