Ranma 1/2 is an anime comic written by Rumiko Takahashi that explores the teenage life surrounding Ranma Saotome. One of the factors which makes this comic amusing is that he gets placed under a curse where whenever he gets splashed with cold water, he turns into a girl. Luckily for him this process is reversable with warm water. Since Ranma is half boy and half girl, that's where the name Ranma 1/2 comes from.
Meanwhile at the Tendo dojo we see a father calling his three daughters Kasumi, Nabiki, and Akane to tell them about an old friend who's coming to visit along with his son Ranma whom he's never even seen before. Their father, Soun Tendo, anounces that one of them must marry Ranma Saotome so that the School Of Anything Goes Martial Arts can be carried on.
A young girl and a panda arrive at the dojo. The young girl introduces herself as Ranma Saotome and much to the surprise of the Tendo's, they realize that he's a she. As they're settling in the Panda takes a bath and is later seen meditating with Soun as a human being. Ranma-chan (girl type Ranma) goes to take a bath and changes into a guy. As he's leaving the bath Akane enters the bathroom and sees Ranma-kun (boy type Ranma). They both stare at each other for a few seconds before Akane leaves and runs away screaming that there's a pervert in the bathroom. At this point Ranma's father Genma (the panda) explains what happened to them.
On a training mission in China, Genma decided to take Ranma to "The Cursed Springs of Jusenkyo." Without bothering to listen to the guide, Genma and Ranma entered combat with each other above the springs. Ranma placed a kick and knocked his father into "Shonmaoniichuan" or "Spring of Drowned Panda". Instead of seeing his father popping out of the spring to resume combat, Ranma instead saw a giant panda. As Ranma listened to the guide as he explained on how anything that falls into that spring takes the body of a panda, Genma gave Ranma a hit and knocked him into "Nyanniichuan" or "Spring of Drowned Girl". Ranma ended up taking the body of a well built teenage girl.
After hearing the story, Soun offered his three daughters for Ranma's choosing as a wife; 19 year old Kasumi, 17 year old Nabiki, and 16 year old Akane. Ranma never got a chance to decide since Kasumi and Nabiki immediately nominated Akane since she "hated boys" and since Ranma was "half girl" after all. Akane had mixed feelings though, "Me, marry that pervert?!" but it was decided on and Ranma and Akane became engaged.
Throughout the anime Ranma and Akane are constantly seen arguing along with her beating up Ranma. Even so they both have feelings for each other yet are too shy to admit them. This is how the anime starts off but is only the beginning. Other characters and events come into play and most of them have some type of "love" for either Akane, Ranma, or even Ranma's female side. Of course Ranma in addition to being "fought over" by four young women he is also "hated" by a large portion of the male cast in Ranma 1/2. Hence he is often seen fighting battles against his opponents but somehow manages to pull through and win almost all the time. Competition is not only limited to martial arts in this anime though, but rather stems from it. For example in competing for Akane's pet piglet, Ranma and Akane must take on a couple in "Martial Arts Figure Skating". And if you think that is weird it goes much farther from there...