In May 1944, five years into the World War II, three Royal Homing Pigeon Service war pigeons soar across the English Channel, with the iconic White Cliffs of Dover looming in sight. These brave messengers carry crucial dispatches to Great Britain. As they near their destination, they find themselves unexpectedly ambushed by a German falcon named General Von Talon. Tragically, two of the pigeons are killed in the attack, while the third is taken captive and becomes a prisoner of war.
Simultaneously, a young wood pigeon named Valiant is engrossed in an Allied forces propaganda film at his favorite haunt—a makeshift bar inside an overturned rowing boat in West Nestington. When Wing Commander Gutsy, a celebrated war hero, flies in to announce that new recruits are needed in Trafalgar Square the following day, Valiant is inspired to sign up. Back in Von Talon’s lair, the captive pigeon Mercury endures brutal interrogation, bravely resisting his captors' attempts to extract information.
With a heavy heart, Valiant bids farewell to his mother and Felix, the local barman, and heads off to London. There, he encounters Bugsy, a scruffy pigeon with a price on his head, who ultimately joins Valiant in his pursuit. Together with new friends: Lofty, an astute red pigeon, and the twin muscle-bound brothers Toughwood and Tailfeather, they form Royal Homing Pigeon Service Squad F and commence their rigorous training under the tough love of their Sergeant.
Meanwhile, General Von Talon devises several schemes to locate the message's departure point, but Mercury remains tight-lipped, even under duress—his resolve ultimately falters when he unintentionally reveals Saint-Pierre. Throughout the trials of training, Valiant finds himself infatuated with Victoria, a kind nursing dove. As the squad's departure approaches, Gutsy informs the Sergeant that they must set off urgently, though their training remains incomplete.
In a twist of fate, Bugsy chooses to abandon the dangerous mission, leaving Valiant and the others to board the aircraft headed for France. However, the voyage turns perilous when their plane encounters intense enemy fire, resulting in severe damage. The pigeons are forced to evacuate in parachute-equipped boxes, but misfortune strikes as Gutsy's gear fails, leading to a fiery crash that seems to claim his life.
Upon landing in France, the pigeons form an alliance with Charles De Girl and Rollo, two resourceful mice from the French Resistance, guided by the adept saboteur Rollo to their target, Saint-Pierre. Unfortunately, disaster strikes again when Bugsy and the message are captured by Von Talon. He seizes the message and plans to imprison Bugsy for a later meal. Valiant and his comrades rush to Von Talon’s fortress, where they learn of Gutsy's miraculous survival.
Using his nimble physique, Valiant stealthily infiltrates the bunker through a gun barrel, retrieves the vital message, and liberates both Bugsy and Mercury. However, the lurking falcons soon catch wind of their escape, prompting a tense chase. As Gutsy and the others engage Von Talon's henchmen, Valiant pushes onward to deliver the crucial message, pursued closely by the fearsome falcon.
In a heart-pounding showdown, Valiant finds refuge in his home, only to be confronted once more by Von Talon. With the aid of his mother and Felix, he ultimately outwits the villain and brings him to a spectacular defeat, ensnared by a giant hook and smashed against the water wheel. Valiant triumphantly delivers the message and is honored with the illustrious Dickin Medal. After this commendable act of bravery, Squad F returns to the bar in West Nestington, where Valiant joyfully reconnects with Victoria.
