Turing Protocol

By: Nick Croydon

Published by HarperCollins Publishers, 2025-12-02

<p>"An incredible debut thriller where the past can be changed to save the future." --Don Winslow, #1 internationally bestselling author</p> <p>A riveting speculative historical suspense debut told in alternating timelines that asks: Will the most powerful invention in history save the world--or destroy it?</p> <p>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.</p> <p>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. Following in her family's footsteps, and bound by Turing's strict principles governing the use of his creation, Annabelle is soon faced with the same impossible choices.</p> <p>Weaving together past and present, The Turing Protocol honors Alan Turing--a genius who was misunderstood and persecuted by his own time--and takes the reader through pivotal moments in history, including the Cuban Missile Crisis, the dissolution of the Soviet Union, and 9/11. All of this leads us to the present day, where Annabelle must prevent major catastrophe--but when the stakes are at their highest, is using Nautilus the perfect solution? Or a risk too dangerous to take?</p>