The story begins with Ranma Saotome and his father, Genma traveling to China so they can train in a sacred area known as Jusenkyo. Jusenkyo is full of springs, each one being different. Hoewever, Ranma and his father are unaware of the curse of Jusenkyo-- whoever falls into one of the springs will turn into whatever drowned in that spring centuries before. Both Ranma and Genma have the misfortune of falling into one of the springs. From that moment on, whenever Genma gets splashed with cold water, he turns into a panda. Whenever Ranma gets splashed with cold water--he turns into a girl.(this is where the 1/2 comes from.)
As you might have guessed, splashing them with cold water turns them back. To make things a little worse, Ranma and his father return to Japan so that Ranma can meet his new fiancee--Ranma has never seen her before. Her name is Akane Tendo, and she is the daughter of Genma's long time friend and training partner, Soun. The two kids were to be engaged in order to carry on the Tendo Anything Goes School of Martial Arts. Just before Ranma and Genma reach the Tendo Dojo, they get splashed by cold water, and there's no hot water to be found. The Tendo family thinks that Genma and Soun are very perverted when they see Ranma standing before them in female form. They then begin to think that it will work out better that way, because Akane is a tomboy, and claims to hate boys.Ranma 1/2 is a hillarious combination of martial arts and romance.