The Mahlström family has been traveling to Södenhagen on the Baltic Sea for 15 years. But this year everything is getting out of hand: Kurt is about to become unemployed and can no longer afford to go on vacation. His marriage to Marga is in crisis and Kurt doesn't dare tell his wife about his difficulties. Pubescent Kati is also in a bad mood because she would rather have gone to France with her friends, and she falls in love with the chaperone Dominik.

A street collapses on a rainy day over a newly made tunnel for a future trainline and captures a bus full of passengers in a hole, slowly sinking into the mud.