The story follows Father Welden, a British Catholic priest sent on a covert mission to negotiate the release of a fellow priest held in a secretive underground prison—the titular "caves of night." As Welden descends deeper into the shadows—both literal and metaphorical—he confronts the brutal machinery of an authoritarian regime and the moral compromises demanded by both religion and diplomacy. Christopher masterfully builds suspense through a slow-burning narrative, layering philosophical questions within a stark, claustrophobic setting. The caves themselves become a haunting symbol of ideological confinement, where characters must navigate their personal beliefs amidst external manipulation. Welden's internal conflict—his struggle to reconcile spiritual values with political reality—adds depth and poignancy to the narrative. Written in the 1950s, The Caves of Night reflects John Christopher's broader themes: the dangers of totalitarianism, the vulnerability of human conscience, and the cost of personal sacrifice. Known primarily for his science fiction, here Christopher demonstrates his literary range and talent for atmospheric storytelling. This is not just a tale of espionage, but a philosophical exploration of what it means to act morally in an immoral world—a thoughtful and haunting novel that remains resonant today.