Four friends are dismal students at most things they try - schoolwork, and particularly sports. When they all entered a race in the swimming carnival at the beginning of the year, the rest of the children criticised their poor performance. They went to their favourite spot by the river to get away from the rest of the school. It was there that they heard a dog barking on the island in the middle of the river where the water was the widest. They swam with great difficulty to the island to find out what was going on. They had to care for the dog and feed it. That meant swimming across the river to the island twice a day, every day, even in winter.