Time is a construct, and we just broke it.
Two young Cambridge University students invent a time machine that accidentally creates a rip in SpaceTime which threatens to destroy the universe. The only way to stop it is to ensure they never create the rip in the first place. So they must travel back in time to prevent themselves from ever being born. But this turns out not be quite so easy, as they have to travel further and further back in time to try change their future.
Along the way they kill Hitler, arrest Jesus, join the Persian army, help the Chinese win the Opium Wars, and make friends with Genghis Khan and his Mongol hordes. They also enlist the aid of two girls from New York, a scribe from the Middle Ages, and a young German policeman.
But no matter how much they try to change the past, the rip keeps growing, timelines get jumbled, and the universe appears doomed. It's going to take something truly extraordinary to sort this mess out.
