Super Robot Wars/3/Story

Six months ago, under the leadership of Bian Souldark, the Divine Crusaders swept across the world in an attempt to forcefully unify it against an alien threat which Bian believed would soon manifest itself. He built a massive robot, the Valcion, and used it in his offensives across the world. The people feared the Valcion, and called together every robot-pilotting hero they could find to fight against it. Thus, Londo Bell was formed from the world's greatest mecha. Bian died with the Valcion at the hands of Masaki Ando and his robot, the Masoukishin Cybaster. The long battle soon came to be known as the Second Super Robot War.

In the months since the battle against the Divine Crusaders, the Earth Federation was formed out of a strong need and desire for a united and peaceful Earthsphere. Londo Bell fell under the Federation's jurisdiction, but the top brass feared their strength and denied them all but the most basic weapons.

Recently, however, military units have been disappearing in the Fifth Luna area. Could the dangling remnants of the DC be responsible, or is a new threat emerging from the shadows? The Earth Federation deploys Londo Bell into the area to investigate...

(source: manual from english game patch)