Teddy and Freddy take their new friends Niklas and Johan on a trip to one of the rocky islets in the outskirt of the archipelago. They also take Båtsman with them, which makes their little sister Tjorven angry, because it's her dog. When Tjorven's parents don't recognize her complaints, she decides to leave the family and become a housekeeper to Söderman. Johan moors the boat too loosely at the rocky islet and when the four young friends are eating fish by a fire, the boat drifts away. Their boat is saved by the girls teacher Björn, who happens to be in his boat in...