The brickworks at which Michael’s father and mother work are going to close down. They are being made redundant. Michael’s father has been thinking about sailing around the world throughout all those years working in the factory. If he had not lost his job, he would not have dared do it. Now that he has lost his job, he thinks that it is the right time to do this once-in-a-lifetime thing. So he has bought Peggy Sue to take the family to sail around the world.
Michael is thrown overboard and lands on an island. At first, an elderly Japanese Kensuke does not want Michael on his island. He wants to be alone. He is very angry that Michael makes fire to attract people’s attention. He wants people to stay away from his island because they will shoot orangutans and gibbons. So he draws a line on the sand to keep Michael away from his territory.
When Michael is stung by jellyfish and becomes paralyzed, Kensuke saves him and brings him to his cave. There, they wash clothes together, go fishing together, fruit gathering together, cook together and do the drawing and painting together. Michael teaches Kensuke English and Kensuke teaches Michael painting. Then, they talk more and become friends.
But, when Kensuke finds out the message in the bottle that Michael sends, he is very upset because Kensuke thinks that Michael does not tell him his feelings as he did. Kensuke keeps Michael at a distance. They do not talk much as before. Later, Kensuke understands that Michael wants to go home and has his long life ahead waiting for him. Unlike himself, Michael just cannot live his whole life on this island. Then they have a friendly reconciliation.
Kensuke reveals that he is too old for the new world after staying on the island for 40 years. It would be very difficult for him to adapt to the whole new world. Japan was his world a long time ago. The island is his world now. Even if Kimi and Michiya are still alive, they are no longer the same persons. They are more like strangers than family. On the island, Kensuke has his new family – the orangutans, the gibbons, the turtles. He will look after them and protect them from hunters and killers. He cannot forget the damage caused to him by WWII.