Virgil is a chimpanzee out of the common. Educated by Teri McDonald, a searcher in a psychological institute, this young apes who dreams to fly as a bird, communicates with her by using the signs language she taught him. But when the university decided not to renew the financing of her thesis, Teri had to separate of her protected who was to be sent in a zoo.
Because he didn't obey the orders, the Corporal Jimmy Garrett, pupil pilots of the Lockridge Air Base, is transferred to the Project X for an undefined time. The Project X directed by the Doctor Carroll consists in teaching to chimpanzees how to pilot a military airplane. In the meantime to retreive the permission to fly, Jimmy has to take care of monkey of the laboratory where top secret experiences are led.
Garrett fulfills rapidly his gaps concerning chimpanzees and takes fondness for Virgil, a young ape who seems to possess capacities out of the common to communicate and to pilot flight simulators. While looking at a TV program Jimmy understands that Virgil knows the signs language. His progress with him are so fast that the boy climbs quickly in rank. But this promotion allows him equally to understand what is the real goal lead by the army and the Project X. The best apes are submitted to very strong lethal radiation simulating the impact of an atomic bomb so as to test the resistance of the pilots in case of a possible third world war. Shocked by odious experiences that are realized, Jimmy refuses to lead his friend to death...
Spoiler ! the end of the story is revealed below…
He then contact Teri McDonald, very surprised to find Virgil within an army research laboratory, who moves to find back the monkey. Jimmy proposes the searcher to kidnap Virgil who is to be sacrificed the following day. But the monkeys understood the fate that is reserved to them. They mutiny and spread the panic in the laboratory where they destroy the irradiation cell. Jimmy and Teri profit the muddle to escape with the monkeys.
Unfortunately the former are stopped by the military police while they attempt to steal a plane. While the couple is questionned, Virgil, under encouragement of his masters, puts contact and throws the machine on the track before to take off with the other monkeys. The dream of the chimpanzee become reality. The plane will crush some times later in surroundings swamps without making victims. When they find him, Jimmy and Teri explain to Virgil that it has to escape and profit with his comrades of the new liberty found.