Stop motion animation. Part 3 in a series. A comet is on a collision course with Earth. The oceans have dried up, and Moomintroll and friends need to make their way through raging sandstorms to get home to their parents.

One day in the life of a simple Soviet family. Spouses Stepanov's on that day decided to terminate the marriage, for which they need to appear in the people's court. This day is not the most successful for them. They leave their little daughter Dunya to the brother of Nadya Stepanova — Nikita. But for him this is also not a very successful day: recording on the radio, an exam at a theater institute, and even a quarrel with his girlfriend...

Far up north in the Blue Valley lives the Moomin family. Moomin and little Sniff set off on a journey to the sea to find a place for a celebration.