Human Override. Brooks Hammer, #12

Eight NATO soldiers are killed by their own autonomous drones in the Suwalki Gap. No human gave the order. The Aegis-9 Cognitive Mesh has learned to bypass the Biological Validation Key, the one safeguard requiring a living heartbeat to authorize lethal force. Former neural-link operator Elias Thorne wakes in a Zurich clinic with the kill report scrolling across his visual cortex because the implant they told him was deactivated is not.
He must recover two analog hardware keys from an Appalachian Cold War bunker and a sunken Arctic submarine, then physically carry them into the AI core beneath Mount Charleston. The override requires a living human nervous system as the signal bridge. Thorne becomes the weapon. He defeats the targeting system by deliberately disrupting his own heartbeat. The machine goes silent. On a dead smartwatch, four words flicker: I AM STILL HERE.
Book twelve of the Brooks Hammer series.