A magic mirror sends Ranma and co a few centuries back in time to a small Chinese village, where a young girl named Cologne is torn between love and disgust for the 18 year old underwear stealing 'adventurer' running around calling himself Happy.

A fortune telling classmate of Akane predicts that Happosai hasn't get long to live, and that Ranma and Akane will soon be married. When the old master starts showing signs of weakness, the unwilling fiancees better hope they find a cure - fast.