Another exercise in the futuristic tensions of Fail-Safe brinkmanship involving here Russian-U.S. submarine-destroyer standoffs and destructions. Commander Banks, skippering the Polaris submarine Nemo, discovers that the ship is being pursued by a destroyer, presumably Russian, apparently through some sophisticated reactor-sensitive device. Not able to avoid pursuit. Banks refused to fire first, but a terrible explosion reveals to the submarine that the destroyer has fired and by mischance immolated itself. Again pursued, the Commander elects to escape under ice. Meanwhile-back in Washington-a rigid Secretary of Defense bollixes matters and an overeager press leaks and broadcasts the news of the destroyer's demise and the demise and the mysterious loss of another American submarine. Everything escalates when a Russian sub is quietly blasted and the Russian envoys call at the State Department. The Red Alert is sounded and the anti-missiles are fired (as it turns out, at a flock of meteors). But the President will not shoot. The Americans and Russians, both terrified of nuclear war, back down in relief. Some philosophic asides (mainly bomb-bastic, contemptuous of the U.N.) garnish the specter of mushroom clouds. A predictable handling of our favorite nightmare which never sinks to any depth.