Tempus Rerum Imperator: Time, Emperor of All Things. The year is 1758. England is at war, embroiled in a globe-spanning conflict that stretches from her North American colonies to Europe and beyond. And now, after more than two years of military and diplomatic setbacks, the country itself is at risk. Across the Channel, the French prepare for an invasion - an invasion rumored to be led by none other than Bonnie Prince Charlie. It seems the map of Europe is about to be redrawn ...again. Yet beneath the surface, behind the scenes, another war is raging. A war that will determine not just the fate of nations but of humanity itself. Daniel Quare is a journeyman in the Worshipful Company of Clockmakers, an ancient guild whose royal charter confers absolute authority over the manufacture of timepieces. But Quare is more than he seems. He is a Regulator, a member of an elite spy network within the guild - a network devoted to searching out and claiming for England's exclusive use any horological innovation that could conceivably result in an advantage for Britain over her adversaries, whether in business or in war. It is just such a mission that brings him one moonlit night to the London townhouse of the eccentric collector Lord Wichcote. But there he finds more than he bargained for. A pocket watch possessed of seemingly impossible properties - deadly properties that seem to have more to do with magic than with any science familiar to Quare or to his superiors in the guild, Sir Thaddeus Wolfe, Grandmaster of the Order, and Theophilus Magnus, head of the Most Secret and Exalted Order of Regulators. But the strange watch has drawn the attention of others as well. The mysterious masked thief known only as Grimalkin, and a French spy - and cold-blooded killer - who seeks to bring the prize back to his masters. Soon Quare finds himself following a trail of intrigue and murder that leads far from the world he knows into an otherwhere of dragons and demigods, in which nothing is as it seems ...time least of all.

In the seventh year of its war against France, England faces threats from abroad and at home, from above - and below. Buoyed by a series of military victories on land and at sea, French forces are gathering for their final push across the Channel. In Scotland, Jacobites loyal to Bonnie Prince Charlie plot to restore the Stuart dynasty to the throne. Beneath the bustling streets of London, a subterranean race prepares to rise. And in the realm known as the Otherwhere - home to dragons, demons and gods - civil war has erupted, causing a great and powerful weapon to be cast into the world. That weapon is a clock - a watch, to be precise, of a size to fit comfortably in a man's hand...a watch with a taste for blood - a mechanism that contains the doom of all that lives. Daniel Quare, of the Worshipful Company of Clockmakers, was sent by his masters to find that deadly time- piece. But he was not alone in his pursuit: both the mysterious thief Grimalkin and the ruthless French spy and assassin Thomas Aylesford were on its trail. But with the help of Lord Wichcote - an aristocrat of many talents and more disguises - Quare succeeded in seizing the watch. But not for long: Aylesford took it from him - and with it, Quare's hand. And now the French spy is on his way back to his masters, Lord Wichcote lies gravely wounded and Daniel Quare has vanished . . . which would seem to mean that all hope for the world is lost...