Jeremy Clockson is so keen about being accurate that he drives his fellow clock makers around the bend. One day, a woman comes to him with a challenge: to create the most accurate time piece ever conceived, what people call a "glass clock." As you can imagine, this draws the ire of The Monks of History, last seen in Small Gods. Toss in Lu Tze and Lobsang, martial arts flicks, rock bands and how teaching should be done according to Susan Sto-Helit running afoul of her school's principal, Madam Frout, and we're off. One small problem, as soon as the clock starts ticking, time officially stops for the Discworld and so too does life as the Disc understands it, which is just fine for the auditors. That is until one auditor finds out just how wrong they were to deny all the things the Disc offers.

If time ends, the world has to end, right? Death, his kolleagues plague, war and famine from the famed four horsemen ride out, agreeing that apocalypse aren't the same these days. All the while two similar brothers, one a talented thief, the other a perfectionist clock maker try to find out- how much time do they actually have till it happens? Slicing time till it is so cut up, she is barely recognizable. And the arbiters of reality, the auditors, also play a role. Is this the end of Discworld, as we know it? The answer might be yes and no.