A new technologically superior Soviet nuclear sub, the Red October, is heading the the United States coast under the command of Captain Ramius. The American government thinks Ramius is planning to attack. A lone CIA analyst has a different idea: he thinks Ramius is planning to defect, but he has only a few hours to find him and prove it. At the same time, the entire Russian naval and air commands are trying to find Ramius too.

Circus saxophonist Vladimir Ivanoff suddenly defects from his touring troupe in that temple of "Western decadence," Bloomingdale's. He wins asylum and moves into the crowded Harlem flat of Black security guard Lionel Witherspoon. Although Vladimir learns that life in America can be cold and even painful, he grows to love what seems to him a strange and wondrous land.