Strange Hill High - Series 1: 2. 99 Cool Things to Do with a Time Machine
Animated series. When Mitchell turns back the hands of the school's clock, he reverses time itself. Soon, he starts mucking about with time.
Animated series following three friends as they investigate bizarre occurrences at their inner-city school.
The really old Strange Hill building is dominated by its really old clock tower, which rises high above the school, chiming away the centuries. As it chimes the beginning of another school day, Mitchell rushes toward school. It's the first day of exams week and, of course, he's late. He sees the clock and has an idea. If he sets it back ten minutes, nobody can claim he's late. So he climbs up and pushes the minute hand back ten minutes. When he enters the school, he finds he's arrived at class ten minutes early! He's actually turned back time!
Mitchell and his friends soon go mucking about with time, setting it forward and backward according to their whims (going back to a particular day when the school lunch was actually good, fast-forwarding through boring lessons, outwitting bullies, etc). But their messing so much with time causes the ancient clock to break and time begins to come apart at its seams! With Becky rapidly ageing forward and Templeton ageing backwards to babyhood, the only help Mitchell can find is a version of himself from earlier and, together, the two Mitchells must literally fix time.