AllMovie

The famous literature professor Martin Lamm (Max von Sydow) has an overprotective wife (Mai Zetterling) who guards him as though he were a national treasure (which he is) and extremely fragile (which he is not). Into this tense but loving household comes the professor's grandson Göran (Carl Svenson), whose divorced parents are too busy to cope with him. Despite the rather grim daytime regime, at night, when his grandmother isn't looking, the boy and his grandfather sneak out of the house for some modest adventures. One day the professor discovers that he has put the wrong letters into the wrong envelopes, and the two of them have an even more extensive and lengthy adventure that takes them all over Stockholm, an adventure which prompts worry on the part of the entire family.