Call of Duty 2: Big Red One is a first-person shooter video game. It is a side-story of the original game Call of Duty 2, which was released on PC and Xbox 360. Big Red One differs from other games in the Call of Duty franchise in that it focuses on a single Allied formation in World War II: the U.S. Army's 1st Infantry Division, which goes by the nickname Big Red One due to their unit patch which features a large, red number one. The game covers the division's part in the North Africa Campaign, the invasion of Sicily, the landing on Omaha Beach in Europe and moving east, and eventually crossing the Siegfried Line into Germany. Each chapter is book-ended with period footage from the Military Channel, with voiceovers courtesy of Mark Hamill (who appeared in the Sam Fuller film The Big Red One), imitating a World War II documentary.