"A captivating, surprising history of timekeeping and how it has shaped our world. For thousands of years, people of all cultures have made and used clocks, from the city sundials of ancient Rome to the medieval water clocks of imperial China, hourglasses fomenting revolution in the Middle Ages, the Stock Exchange clock of Amsterdam in 1611, Enlightenment observatories in India, and the high-precision clocks circling the Earth on a fleet of GPS satellites...

Hidden away at Hopewell Elementary School is a magical locker that always delivers a solution to your problems--just not quite in the way you might expect. When Keisha James forgets to do her science homework, Locker 37 gifts her with a clock that can rewind time--how will she use her second (or third...or fourth) chances?