Three children find a treasure map in their Grandpa's shed and he tells them the story of how he came by it. It was from a time when he was a boy in the early 1960s. The story follows the adventures of seven children who are together over the summer holidays on a farm. While out fishing their boat is blown ashore onto a "forbidden island". They meet a fascinating old man on the island who claims to be a survivor from an ancient civilisation that had discovered a youth potion that enabled him to live for thousands of years. He tells the children that they were all once citizens of this ancient land in previous lives and that they had been chosen to seek for certain "moral truths" about themselves. Once each child has discovered their own "truth" they would be able to find the treasure that existed on the island. The old man warns them that there is another survivor living on the island who is an evil wizard and strongly advises the children to avoid him. The story then follows the children's' quests for their moral truths which are encountered during the various adventures they have on the farm and in subsequent visits to the island. The adventures include horse riding, shooting, swimming, playing in an old "haunted house" and many other activities that country children engaged in before the age of television, computer games and smart phones. They encounter the evil wizard on a later visit to the island and become embroiled in a struggle of good versus evil.