Pluto is planning to kill billions for her vision of Crystal Tokyo and it’s up to the Saotome’s who are descended from Serenity’s line to stop her. They impregnate Ranma with DNA from queen serenity, they baby is engineered to grow up in two years and will prevent the great freeze. Ranma feels betrayed and eventually escapes, on the run she is hunted by her Family and the Senshi are trying to kill her. She is rescued by Chibi-Moon and Saturn when the Senshi find her and is able to prove Pluto was wrong and the great freeze is actually a prelude to invasion from Beryl’s clone and a million Youma who must be stopped. (Sailor Moon Crossover.)