With his last breath Uu's friend entrusts him with the secret of how to go to the past. Uu is an engineer and doesn't believe in miracles, but the trick works. In the past there is a pleasant, eternal summer, long hair, girls and Jenkki chewing gum. In his real life, it is autumn, his friends are bitter, the girls are married and his father is seriously ill. At the end of the day, however, Uu has to decide in which time to live his life - in the summer of the past or in the autumn of the present.

Somewhere in Europe by a great sea stands a small village, where inventing all manner of domestic gadgets is held in great esteem. Every year the villagers organize an annual competition of new inventions. One of the best inventors in the village is Oskar, Lotte's father. His primary rival is Adalbert, whose wife also partakes in the competition. On the eve of the next competition, Lotte and her friend Bruno find a book soaked in the sea, from which Susumu, a gardener from distant Japan, climbs out. Susumu teaches the villagers some judo throws before a big judo competition, which the latter will eagerly use to facilitate their daily lives.