Jonah Wiley is a 12-year-old boy fascinated by clocks and watches. He's going through a tough period. He's angry because his parents are divorced and his father has remarried. When his mother goes off on a week-long conference, Jonah has to stay with his father, stepmother, and younger stepbrother, Toby. Because Jonah feels he doesn't belong, he steals his father's antique pocket watch. When Toby winds the watch, the two boys are hurled back into the past, first to Memphis in ancient Egypt, then to various centuries in China, France, England, the United States, Ireland, and even Canada. As they travel through history, the boys discover interesting information about time and how it was measured throughout the ages. But there's one big problem: Jonah and Toby must race against the clock, or be stuck in the past forever.