Time is a resource. Everyone knows it must be managed. You can let it move fast or slowly, but what you mustn't do is allow it to stop.

On the Discworld, the History Monks have the important job of ensuring that tomorrow always comes. But the construction of the world's first truly accurate clock starts a race against, well . . . time.

Monk Lu-Tze, his apprentice Lobsang Ludd and Death's granddaughter Susan must stop the clockmaker before he completes his task. Because a truly accurate clock will stop time completely.

And then, there really will be no tomorrow . . .