Mike Walden never knew his father, who died in the unexplained sinking of the US submarine Snapper two decades ago in 1968. When he asks newspaperman David Evans for help, the reporter is captivated by the mystery and agrees to probe Snapper's loss. As he learns of classified files and secret missions, what Evans doesn't know is that his investigation is on a collision course with both a KGB operation to infiltrate the US government and the FBI’s efforts to stop it. Tension gradually builds as both the Navy and the KGB try to keep Evans from uncovering their secrets, leading to a nerve-wracking superpower showdown.