About this book:

Dr. Marcus Thorn spends his days restoring damaged maps and avoiding the complications of ordinary life—until a mysterious trunk arrives from the uncle he hasn’t heard from in twenty years. Inside are journals, forbidden charts, a brass compass that no longer points north, and a vellum map marked with a cipher beneath the ink. Then a stranger calls with one warning: burn it before they find you.

When Marcus decodes the first clue—“where London forgets it has a river”—he is plunged into a hidden world of buried waterways, secret societies, and maps that seem to rewrite history before his eyes. Soon he is hunted through dark archives and forgotten tunnels by men who know exactly what his uncle died for.

From London’s shadowed undercity to Edinburgh, Istanbul, and the Alps, The Cartographer’s Secret Cipher is a pulse-pounding thriller of ancient clues, modern assassins, and a truth so dangerous it has been erased from every map.