At the start of a naval court-martial, Barney Greenwald, a skeptical naval lawyer, reluctantly agrees to defend Lt. Steve Maryk, a first officer of the Navy who took control of the U.S.S. Caine from its domineering captain Lt. Philip Francis Queeg during a violent sea storm in unfriendly waters. As the trial progresses, Greenwald becomes increasingly concerned and questions if the events aboard the Caine were deemed a true mutiny or simply the courageous acts of a group of sailors who did not trust their unstable leader.