Ten-year-old Jack is stranded on a desert island. He's been very lucky: he's survived a terrible storm and the mysterious island he has found himself on has a kindly if unusual inhabitant, fresh water and plenty of food. But Jack needs to find his way home, and as he uncovers incredible hidden treasures on the little island, he starts to formulate a plan.

A plan that will involve witchcraft, terrifying sea monsters and pirates! But if Jack's going to succeed he will need to be very very lucky.