After Pearl Harbor, the US Navy's only real advantage against Japan is a small, overworked cryptanalysis unit in a basement in Hawaii. This film follows Joseph Rochefort, a naval officer with a gift for crossword puzzles who leads the team racing to break JN-25, the Japanese fleet's operational code. Interviews with historians and archival footage trace how Rochefort's station pieced together intercepted signals into warnings about troop movements and fleet positions, culminating in the intelligence that let the US Navy anticipate the attack on Midway rather than simply react to it. The film lays out the mechanics of the codebreaking work itself, the arguments between rival intelligence units over resources and credit, and the pressure of delivering conclusions that admirals had to act on with lives at stake. It treats Rochefort less as a war hero in the conventional sense than as a puzzle-solver whose work in a windowless room reshaped a naval campaign, and it makes the case that Midway's outcome owed as much to signals intelligence as to ships and pilots.