Ranma 1/2. 2-in-1 Edition. Volume 1: Rumiko Takahashi

One day, teenaged martial artist Ranma Saotome went on a training mission with his father and ended up taking a dive into some cursed springs at a legendary training ground in China. Now, every time he's splashed with cold water, he changes into a girl. His father, Genma, changes into a panda! What's a half-guy, half-girl to do?

Years ago, Genma promised his old friend Soun Tendo that Ranma would marry one of Soun's three daughters and carry on the family's martial arts school. Except that the girl picked to be Ranma's bride doesn't seem to like him, Ranma keeps getting into fights…and did we mention that whole changing into a girl thing?