The events take place in the world of the Forty Islands. Aliens have created an artificial playground to study the behavior patterns of hopeful Earth children. They began cloning real children and then placed them on one of the islands, where they had to fight others for a chance to return home. The children realize that all this time they have been under a dome, rebel, and break through the dome. Only the main hero and his best friend manage to find a passage and return to Earth.