In the midst of the Cold War, a highly skilled Soviet submarine captain, Marko Ramius, takes command of Red October, a state-of-the-art nuclear submarine equipped with an innovative stealth propulsion system known as "the caterpillar drive," which renders it nearly undetectable to acoustic tracking. Against the backdrop of political tensions between the United States and the Soviet Union, Ramius and his officers murder their political officer and set a course for the North Atlantic, defying orders from the Soviet Navy. As the Red October embarks on its rogue mission, the incident quickly escalates into a high-stakes game of cat and mouse.

The U.S. Navy, upon becoming aware of the situation, deploys its forces to track down and intercept the rogue vessel. Meanwhile, CIA analyst Jack Ryan, an expert on Ramius who is familiar with his unconventional tactics, deduces that the captain's motives may not align with the Soviet's expectations. Ryan is air-dropped onto the aircraft carrier USS Enterprise and becomes immersed in the operation. He must convince the American military command of his theory about Ramius's intentions before potential conflict erupts between the world's two preeminent nuclear powers. As ships and submarines from both nations converge in the Atlantic, the ensuing conflict threatens to spark a catastrophic confrontation under the waves.