This novella explores fertility, masculinity, marriage, and tropical fish in contemporary Japan.

There are three interconnected scenes in the book. The connection is the narrator and one of his male friends called Saiki. The Narrator has a wife and they want to have children.

In the first story, the narrator and Saiki visit a friend of Saiki called Urabe who lives above a failed pet shop with a lot of tropical fish. When they arrive, the two men find that Urabe is not only married but has a baby too, something Saiki was not aware of.

In the second story, the narrator and his wife visit Saiki who also has a new wife called Yoko and has moved to the country. They eat local rural food and discuss how to remove the weasels in the attic which are causing problems for Yoko and Saiki.

The third segment is also set at Yoko and Saiki’s house after they’ve had a baby together. There’s a blizzard and the narrator and wife have to spend a night in a room lined with fish tanks and the narrator has a weird fish-related dream. The book ends with a revelation to the narrator provided by a neighbour of Yoko and Saiki’s.