Even though their parents disappeared during a hunt three months ago, seventeen-year-old Indi and his siblings, Beleza, Oscar, and Zulu, continue to roam the Mediterranean on their sailboat and hunt down monsters--but Indi yearns for a more settled life for his family, and he hopes that his parents' journal with its tantalizing hints of a treasure, will provide them all with the means of escape from their nomadic and dangerous life before it is too late.