World War II is raging across Europe and the German army has their sights set on England. Messenger pigeon Francis carries important notes back and forth between England and her allies, and wants nothing more than to do his part for the war effort. But when Francis is injured on an assignment to deliver the most important message of the war—one which warns of a coming attack on Britain itself—he finds himself stranded in the middle of the London Zoo with no way to complete his mission. Ming, the world-famous panda, has so far managed to avoid being caught up in the war. But that's getting harder and harder to do as the zoo suffers under dwindling food rations and German air raids threaten the city every night. When Francis lands in Ming's enclosure, she knows she can no longer stand by and do nothing. Enlisting the help of a kind zookeeper and a resourceful troop of monkeys, Ming fights to help Francis recover his strength so that he can carry out his mission. But when the war finally arrives in London, threatening everyone in the zoo, Francis, Ming, and the other animals must work together to save themselves...and maybe even London itself.