When Annie's Uncle Marco goes on one of his frequent trips, he leaves two sealed boxes in Annie's care. His instructions are clear: under no circumstances should she open the boxes. But, left alone with her uncaring aunt, there is little to distract Annie from the mystery of the boxes, and soon she is consumed by an overwhelming desire to open them.

When finally her willpower gives out, she unleashes a creature which reproduces at an alarming rate, and, even more incredibly, a force which can slow down time. Then the Crutchley Development Company discovers her secret, and sets out to harness the power of the boxes for their own despicable purposes. But they bargain without Annie and her friend Henry's determination to stop them - and their courage in taking on the nature of time itself.

This book is part of a book series called Hodder Silver .

There are 176 pages in this book. This book was published 2000 by Hachette Children's Group .

William Sleator is the best-selling author of many novels for children. Hailed by R. L. Stine as 'one of my favourite young-adult writers,' Mr Sleator divides his time between homes in Boston, Massachusetts and rural Thailand.