Earth Orbit
An Earth Federation transport ship makes its way towards Earth, carrying fresh soldiers and supplies to the terrestrial frontlines. Among its passengers are young officer Shiro Amada and a teenage recruit named Michel Ninorich. When they spot a mobile suit battle underway in Earth orbit, Shiro launches in a space pod to assist Federation pilot Terry Sanders Jr.

Shiro's pod and the Zeon mobile suit are both destroyed in the skirmish, and the two pilots take refuge inside the drifting hulk of a space warship. Shiro and the Zeon pilot, a young woman named Aina Saharin, are forced to work together to contact their allies and escape.

On the Frontlines
Upon arriving in Southeast Asia, Shiro takes command of the 08th MS Team of the Kojima Battalion. In addition to Michel and Sanders, the team is made up of pilot Karen Joshua and hovertruck operator Eledore Massis, and is equipped with three pre-production Gundam mobile suits designed for ground combat.

At first, the inexperienced Shiro has difficulty earning the respect of his teammates and fighting in the jungle environment. On his very first mission he gets lost in the forest and has another chance encounter, this time with a girl named Kiki Rosita, the daughter of a local guerilla leader. And on his next outing Shiro is captured by the guerillas, but is able to persuade them to team up with the 08th MS Team to capture a Zeon frontline base.

The Apsalus Project
Meanwhile, Aina has also arrived on Earth. Here she is reunited with her brother Ginias, a Zeon military researcher who is developing a powerful new mobile armor, known as the Apsalus, at a secret base on the Tibetan plateau. Aina takes the Apsalus on a test flight, leading to an unexpected skirmish with the 08th MS Team. The damaged mobile armor is soon recovered by the Zeon forces, and Ginias continues his work with even greater determination.