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.
Pekka Puupää and Pätkä involuntarily end up in Suez as peacekeepers. After saving the Caliph's daughter Suleiman from kidnappers on two occasions, the Caliph magically reunites the friends with Justiina.
Trade counselor Lillukka leaves his entire fortune to Pekka Puupää, who, thanks to cartoons and films, has become closer to him than his immediate family, who are pursuing their own interests. Pekka starts running a toy factory and hires a freckle-faced bowling boy as the company's errand boy. Widowed trade counselor Gunilla Lillukka tries to get married to Pätkä, who has been promoted to assistant director.
