The madness continues.... In this volume we start with learning Ranma's "sole" weakness (I mean, other than his cockiness and his fear of being seen as girlish, and his general refusal to admit his feelings). No, we learn that he's frightened to death of cats because of training his father put him through when he was ten - the Neko-Ken (aka "Cat Fist"), where he *becomes* a cat. This leads to an adorable moment where Akane calms him down with catnip and he crawls into her lap, purring, and kind of kisses her. And has no recollection of it the next day, which makes her upset that she could've been anyone ("Do you really think I'm that kind of guy?"). This leads to an argument, interrupted by a package arriving. It's a cat - who is Shampoo. She's back, after training in China and falling into the spring of drowned cat. This made her realize that Ranma really is a guy, and therefore her husband-to-be.
Shampoo brings two new cast members into the story: Mousse, the practically-blind martial artist who's been in love with her his whole life, and Cologne, her withered great-grandmother, who's also a martial arts master. Mousse and Ranma fight each other (Mousse wants the winner to get Shampoo, but Cologne objects, so he says that the winner gets Akane). Cologne, however, has tapped Ranma in the chest, hitting a particular pressure point that makes him unable to endure warm or hot water. He ends up stuck in girl-form.
She has the cure, a Phoenix Pill, and says he has to steal it from her. This leads Ranma to learning the Kachu Tenshin Amigurikan (called "Chestnuts Roasting on an Open Fire" in the translation), which allows him to punch hella-fast. At the beach, Shampoo is deemed the prize for... wait for it... a martial arts watermelon splitting race. Ranma, Akane, their fathers, and Cologne appear to be winning, but when Akane pulls ahead Shampoo decided to fight her. Ranma is told that whoever he kisses will be the winner - but in classic Ranma style, he looks like he's gonna make a move for Akane (though Shampoo is telling him he'll only get the Phoenix pill if she's chosen), and she kicks him toward the finish line when he makes it clear he isn't choosing anyone.
At the finish line, he begins his all-out fight with Cologne, using his new technique. But is it enough??
I think my favorite aspect of this volume is when the Martial Arts Watermelon-Splitting Race is announced, random guys in the crowd ask "what is that?" and say "that's a stupid idea." It's a lot easier to take in ridiculous challenges and such when even the author is acknowledging how dumb they are. :P
I also feel that this is the volume that really begins putting the pressure on Ranma and Akane as a couple. If Shampoo had remained in China, I think facing their feelings would've been a lot easier. We still have a bunch of crazy external pressures on them, but Akane's jealousy of Shampoo pushes them a few steps backward. Also, Shampoo and Cologne give more chances to show that Ranma will do anything to meet his goals, be it finding a cure or proving that he's the best martial artist. When he agrees that the winner of his duel with Mousse will be Akane, he doesn't even blink. There's no "Akane is MY fiance" moment - so we as the reader don't know if it's arrogance driving him, or love/protection of Akane. And she doesn't know either - so keeping his feelings in the dark is also a narrative key to keeping Akane insecure in their friendship.