Following the events Jerry Mitchell encountered in Dangerous Ground, the pilot-turned-submarine officer is now a department head, the navigator, aboard USS Seawolf. Now on a mission deep in the Barents Sea, north of Russia, Seawolf explores the sea floor, part of a sophisticated reconnaissance plan that will watch the Russian navy as it trains for battle. Although well outside Russia's territorial waters, Seawolf is ambushed by Russia's newest submarine, Severodvinsk. Although it doesn't fire any weapons, its aggressive new captain, Alexi Petrov, harasses the intruder with dangerously fast, insanely close passes by the American boat.
The two subs collide, with the Russian boat crippled and trapped on the bottom. Only Seawolf knows where she is, and the rest of the Russian fleet is too angry to listen. Mitchell and his shipmates have to keep their own damaged boat afloat, figure out a way to make the Russians listen, and keep the trapped Russian submariners alive until they can be saved - if that is even possible.