The story centers on American submarine Captain Joe Glass (Gerard Butler), who is tasked with a mission to rescue a kidnapped Russian president and prevent a potential World War III. The movie starts with the mysterious sinking of a U.S. submarine in the Arctic Ocean. Captain Glass, known for his unorthodox methods and extensive experience, is assigned to investigate the incident. Concurrently, a team of Navy SEALs led by Lieutenant Bill Beaman (Toby Stephens) is sent to reconnoiter a Russian naval base, where they uncover an ongoing coup.

As tensions rise, Captain Glass must navigate treacherous waters and collaborate with Captain Andropov (Michael Nyqvist), who commands a rogue Russian submarine. Together, they form an unlikely alliance to thwart the coup, rescue the Russian president (Alexander Diachenko), and avert a global catastrophe.