The follow-up to the bestselling novel The Turing Protocol.

Nautilus is a machine with the astonishing power to send messages eight weeks back in time. Its users must follow a set of protocols established by its inventor, Alan Turing, including that it can only be used by a descendant of his family, and only to avert global disasters.

But what would happen if it fell into the wrong hands? The machine is in the custody of Turing’s granddaughter, Annabelle, but she’s unaware that her husband, Edward, is plotting to use it for his own personal gain.

And Edward isn’t the only one with designs on the machine. Other rogue operators want to harness its abilities, and they have even bigger targets in their sights: they want to use it for power, manipulation and even to bring down nations.

Will the machine’s capacity for good outweigh its potential for catastrophic harm? In this follow-up to the bestselling The Turing Protocol, the fate of Nautilus – and of the whole world – is on a knife’s edge.