The fog is coming in from the sea at the outskirt of the archipelago. When Johan, Niklas, Teddy, Freddy and Båtsman leaves the rocky islet out there, they get lost with their boat in the fog. Back home on Saltkråkan people hear about the fog in the weather report. Melker is alarmed. Nisse tries to calm him down, by pointing out that the sea is anyhow dead calm. The four young friends and the dog finally arrive at an island. They rove about until they find out it's the island where the school is.

On midsummer, Malin is courted by Christer but the children do their best to stop him.

In a book Melker finds the maxim "This day - a life". He decides to make the maxim come true this very day, but despite his good intentions, all his undertakings end in disaster. He builds a water-conduit to the kitchen, only to find out that the whole kitchen-floor is flooded with water. He cook fishes for the dinner, but the food is uneatable because of too much salt. Christer invites Malin to a boating excursion and is not happy when she brings along her little brother Pelle. In the end Christer leaves Saltkråkan with the intention of never coming back.