Ever since they were born on the same day, eleven-year-olds' Gemma and Alice have been the best of friends, sharing everything from birthday wishes and secrets to laughter and tears.

A Psammead is 'It', an ancient, irritable, ugly sand fairy, which five children find one day in a gravel pit. As a reward for finding him, It grants the children one wish a day, the results of which will last until sunset.

Working from his home in a converted windmill, Jonathan Creek is a magician with a natural ability for solving puzzles. He soon puts this ability to the use of solving impossible crimes and mysterious murders.