The Tendo family is suprised to find a strange panda and red haired girl on their doorstep one rainy day. They learn that the two are actually Saotome Genma (an old family friend) and his son Ranma who have been transformed by the Jusenkyo curse. The curse causes both Ranma to become a girl and Genma to become a panda when in contact with cold water. The only way for them to return to their normal male, human states is to come into contact with warm water.
With the problem of Ranma's periodic femininity, Genma and Tendo Soun are now faced with the challenge of pairing Ranma with Tendo’s daughter Akane for the sake of “Anything-Goes” martial arts. Despite Ranma and Akane’s supposed disinterest in one another and constant bickering, the two find themselves fighting against those who would tear them apart.