Mobile Suit Gundam 0080: War in the Pocket (1989)

The story of a young boy who (along with all his friends) idolizes the pilots of the giant military robots. When he finds a soldier and his robot hidden in the forest, the boy quickly agrees to help this new friend, not knowing the soldier is an enemy spy. As the war between the two nations grows in intensity, the boy comes to learn that the war is not as simple as it seems, and that good and evil are not what everyone says they are.