Ranma Saotome, a teenage martial artist, and his father Genma travel to the 'cursed training ground' of Jusenkyo in China. There, despite the warnings of the Chinese guard, they fall into the cursed springs. From now on, whenever Ranma is doused in cold water, he turns into a girl and a cute, well-built redhead at that. Hot water changes him back into a man again, but only until the next time. To make matters worse, his father engages him to Akane Tendo, a girl who hates boys.

With the Tendos, the Saotomes, Ryoga, Shampoo and Ukyo misinterpreting Tatewake Kuno's invitation to his two loves, Akane and 'The Pig Tailed Girl', to try his new yacht, a whole new episode of chaos begins in the already unstable lives of the Saotome/Tendo clan. A mysterious shadow kidnaps first Akane's sister Kasumi, then continues on until all the girls disappear. All except everyone's favorite hydrotranssexual.

When Prince Kirin of the 7 Lucky Gods shows up at the Tendo dojo looking for his bride-to-be, guess who's accidentally holding the scroll that signifies his future mate? Why, Akane, of course, and the rest of the Ranma crew is forced to take a boat to China in order to save her from the horrors of marriage and a diet of pickled vegetables.

Shampoo discovers a broach which makes her feel the opposite of her true feelings for Ranma. Ranma begins to panic at the thought of losing one of his fiancees, and plans to tell Shampoo that he loves her.

Kasumi has a dream that Santa Claus asks her to hold a Christmas party at the Tendo Dojo. Practically everyone from the series is invited and chaos ensues.

Following a string of food thefts, Akane heads out to find the culprits when she runs into the sisters Natsume and Kurumi who soon follow her to the Tendo Dojo. Seeing how hungry the pair are, the Tendos decide to take them in. However, the sisters then reveal that they're searching for their father, Soun Tendo!

The plot focuses on the fallout from Ranma and Akane's initial defeat by Natsume and Kurumi, two orphan sisters who believe Soun Tendo is their long-lost father and intend to claim the Tendo Dojo.

Akane Tendo meets her new fiancé, Ranma Saotome, a martial arts prodigy with a twist: he magically transforms into a girl upon touching cold water.

Happosai fed up with Ranma interfering with his hobby, decides to use a sleeping incense on him to make Ranma "sleep till spring". But Akane accidentally smells the incense and due to unforeseen side effects starts attacking everyone and everything in her sleep. Now the gang has to find a way to wake her up.