A group of young university students on a sailing trip anchor their boat off the coast of a remote island. They meet the island's owner and his daughter. One of the young men decides to stay on the island for the whole summer and ends up uncovering its dark secret.

Uuno disguises as an old man and infiltrates a nursing home for rich old people, where his father-in-law also lives. The ever-hungry Uuno is seduced by the table groaning with food, but as it happens, he never manages to be there at dinnertime. Meanwhile Sörsselssön enters Uuno for a TV competition named This Is My Life, where contestants tell about their life as viewers vote them either to continue or out of the show. The nursing home elderly watch on TV as Uuno tells the show's host his life story.

Uuno is forced to complete his mandatory military service when it is revealed that he only spent one day in the army in his youth. As is typical of the Turhapuro series his family and friends become closely tied in with these events. His friends Härski Hartikainen and Sörsselssön return to the army for a refresher course and by chance Uuno's father-in-law, Councillor Tuura is made the Finnish Defence Minister. In one of the most memorable scenes, Uuno's wife, Elisabeth, dresses as Uuno and substitutes him for a day as Uuno has an apparently urgent meeting (at a restaurant) and while becoming lost in the woods with a malfunctioning radio, Tuura accidentally declares war on Sweden.

Uuno's nose is proved to be so good, that he can smell behind the display window what goods are on the other side. With this fabulous smell talent Uuno is chosen to Police's police-dog school as a student among the other dogs. Meanwhile Director Tuura, Uuno's father-in-law has been chosen to a very high office and thinks that Uuno is just gaining bad reputation for him, so he decides to broake Uuno's and Elisabet's marriage.

Uuno Turhapuro finds his doppelganger, Hugo, who happens to be a computer genius. Hugo helps Uuno save his father-in-law's business (and Uuno's inheritance) while Uuno helps Hugo win the heart of the love of his life.

Uuno Turhapuro has lost his memory and thinks he's a woman. His friend Sörsselssön has lost his memory too and Härski Hartikainen tries to help them.

Gangsters try to steal Uuno Turhapuro's father-in-law's money by infiltrating into the family through Uuno, by pretending he has a long-lost son.

Uuno Turhapuro's younger brother Peni arrives in Helsinki. Uuno helps his brother in management duties.

Uuno is working as campaign manager of a president candidate but accidentally Uuno himself becomes the president of Finland.

Uuno Turhapuro becomes the President of Finland. Streets are named after him and honorary companies are arranged for him. He also tries to turn Finland into a kingdom.