Fem barn vars pappa krigar på frontlinjen får bo hos deras farbrors herrgård och då träffar på en älva som heter It. 'It' is a Psammead, an ancient, ugly and irritable sand fairy the children find one day on a secret beach at their uncle's mansion. It grants them one wish per day, lasting until sunset. But they soon learn it is very hard to think of really sensible wishes, and each one gets them into unexpected difficulties. Magic, the children find, can be as awkward as it is enticing.