The Inner Sphere, an area of space roughly centered on Sol is at war. Five ruling houses, those of Kuno, Gosunkugi, Shiratori, Joketsuzoku and Tendo vie for control, fighting with giant Battlemechs. On planet Lightoller, Ranma and his father, dispossessed mechwarriors on a quest, are desperately trying to escape the vengeful Shampoo, after them for breaking into the top-secret Jusenkyo Laboratories. Luckily they escape, but they bear the mark of Jusenkyo now in the curses they carry. But Genma has an old friend that might help. In the Nerima Confederation, itself under attack from Kuno's Furinkan Combine and Gosunkugi's League of Five Nails, the Tendo's, the youngest daughter Akane particularly, wage war on their enemies. But the war appears hopeless. Just when it seems that the end has come, Genma and Ranma arrive, bringing hope in the form of a chance to find the legendary planet Ryuugenzawa. And chaos in the form of an arranged marriage to Akane. Something that Kuno and Gosunkugi are both violently opposed to...