In a world of secrets, some corridors lead to power—and others to ruin. In A Spy Inside the Castle (December 9, Castlemartin), debut author M. B. Courtenay launches a cerebral espionage series that blends the psychological intrigue of John le Carré with the immersive prose of Donna Tartt. Ethan Briar, a reluctant intelligence operative, is sent into a political labyrinth to uncover a mole threatening U.S. security—only to discover the “monster” at its center may be the system itself.

With an audiobook narrated by Grover Gardner (Game of Thrones, David Baldacci), Courtenay’s high-stakes debut asks: Would you support an all-controlling secret regime if it was the only thing keeping humanity from chaos?

Here’s more about the book: Ethan Briar was never a spy. He predicted risks—he didn’t take them. But when a cryptic message warns of a hidden war, he’s drawn into the shadows of Castlemartin Manor, a decaying stronghold hiding a conspiracy-driven regime.

At its heart lies ARCLIGHT, a quantum supercomputer built to predict the future. But ARCLIGHT’s inner circle doesn’t just forecast events—it controls them. Nations rise or fall by its design. Now, as ARCLIGHT turns its gaze on him, Ethan must navigate shifting loyalties, encrypted legacies, and the politics of modern intelligence to unmask FOXGLOVE, an operative whose betrayal could set the world on an irreversible path.