In May 1944, 5 years since the declaration of World War II, three Royal Homing Pigeon Service war pigeons are flying across the English Channel with the White Cliffs of Dover in sight, carrying vital messages to Great Britain. Despite the poor weather conditions the pigeons have nearly reached their destination. They are, however, suddenly ambushed and attacked by a German enemy peregrine falcon named General Von Talon; two of the pigeons are instantly killed, yet the third, Mercury, is taken as a prisoner of war.
Elsewhere, a small wood pigeon named Valiant is watching an Allied forces propaganda film in his local bar (an overturned rowing boat) in West Nestington. Wing Commander Gutsy, a war hero flies into the bar, informing everyone that signups are scheduled the next day in Trafalgar Square, London. In General Von Talon’s lair, Mercury resists interrogation by his captors. Valiant flies off to London, bidding his mother and Felix, the local barman, goodbye. In London, Valiant meets an unhygienic slacker pigeon named Bugsy, who is being hunted by two thugs, after having tricked them at a shell game. In order to escape the thugs, he signs up with Valiant.
The recruits, Valiant, Bugsy, Lofty, an intellectual red pigeon, and Toughwood and Tailfeather, two muscular but dim-witted twin brothers, form Royal Homing Pigeon Service Squad F, and are sent to a recruit training facility. Under the command of Sergeant Monty, who declares that he will toughen them up for the RHPS, the training begins. Meanwhile, Von Talon and his henchmen, Cufflingk and Underlingk, try numerous attempts to discover the message’s departure location. However Mercury refuses to tell, despite the tortures inflicted upon him, such as irritating him with yodeling music and injecting him with truth serum, before Mercury accidentally reveals the location: Saint-Pierre.