Centuries in the future, in the year After Colony 195, Earth is surrounded by orbiting space colonies. The colonists are cruelly oppressed by the Earth Alliance, which uses huge humanoid fighting machines called "mobile suits" to control the populace. Behind this tyranny is the secret society called "Oz," which has infiltrated the Alliance military and steered it towards its repressive course.

Now, the space colonies are ready to strike back. Five young pilots, equipped with advanced mobile suits called "Gundams," are sent to Earth to wage guerilla war against Oz and its Alliance puppets.