In the midst of World War Two, Enigma codebreaker Alan Turing finds himself on the brink of a discovery that will change the world: a way to send a message back into the recent past. But when his invention successfully averts disaster on D-Day, the danger it poses in the wrong hands becomes terrifyingly clear. As Turing’s enemies close in, only one decision is possible: Nautilus must be kept hidden from the world, safe in the care of the only person he can trust.
Seventy-five years later, Annabelle McIntosh’s life is upended when she learns she will become the latest custodian of the greatest secret of the modern age – Turing’s Nautilus machine.
