As the Allies prepare for the D-Day Invasion, a pigeon named Valiant (Ewan McGregor) wants to contribute to the war effort. With carrier pigeons being decimated by German falcon Von Talon (Tim Curry), the understaffed Royal Homing Pigeon Corps accepts pint-sized Valiant and his shady friend, Bugsy (Ricky Gervais). After surviving training, Valiant is sent on a dangerous assignment to rescue Mercury (John Cleese), a messenger bird taken prisoner by the Nazis.