This is only going to be a general (and opinionated) overview of the series, focusing on Kaoru, naturally. Once the anime breaks from the manga, I start talking about the manga. Also, please note: This summary is not an acceptable substitute for any real summary. Consult my links page if you want that.

Kaoru's life prior to the beginning of the series is sketchy. Since she's an only child, I would guess that her mother probably died when Kaoru was pretty young. From various bits of the anime and manga we can assume that her father raised her as the heir to the Kamiya Kasshin Ryu, saw to it that she was educated to a point, and generally probably doted on her. I seem to have gotten it into my head that at the beginning of the series Kaoru's father has been dead for about two years, but I can't find any confirmation of that at the moment. At any rate, the series begins when Kenshin, recently arrived in Tokyo, is attacked by some girl who mysteriously knows to call him the Hitokiri Battousai. Of course, she's looking for someone else, a man who's been killing people in the name of her dojo, and using Kenshin's discarded identity. She wants to defeat him, bring him to justice, and clear her name. Kenshin rescues her once or twice and then moves in with her. Over time, they acquire a couple of new companions. After a run-in with Yahiko, they free him from the local gang that was making him pick pockets for them, and Kenshin makes him Kaoru's student against the will of both. Sano joins them after Kenshin defeats him, and sets about sponging off Kaoru. (He doesn't live at the dojo... how does he ever make rent?) They also rescue Megumi from a higher level of organized crime, and the vixen promptly latches onto "Ken-san" and antagonizes Kaoru. (Should have just let her stab herself, Sano-kun....) Kaoru's baka deshi does his best to get himself killed for the sake of proving his manliness and helping his crush Tsubame. Sano and his friend, Katsu the Attractive Artist Guy (my friends canNOT remember Japanese names, so we get all these vaguely amusing titles for people instead) head off to blow up government buildings, and Kaoru reveals something of a crush on Kenshin when she gets drunk. Like we didn't already know. The Yutaro storyline happens; in the anime it's noteworthy for that scene where Kenshin inadvertantly reveals all to the girls, and in the manga, Yutaro gets a crush on Kaoru. I like that. The anime has an abnormally stupid filler story in which Kaoru trains a sumo wrestler... ::shudder:: The pirate story, focusing on Kenshin and Kaoru's feelings for each other (Kenshin takes Kaoru's place when she's kidnapped and is willing to die for her... the filler pirate-chick gets a crush on Kenshin) is possibly the best of the bunch, not that that's saying a lot. Then, we hit the Kyoto Arc.

Saitou makes his appearance and whatnot, wounds Sano (damn him!) and fights Kenshin (grrrrrr.....) After this, Kenshin, despite resistance from his friends, decides that he has to go to Kyoto to stop Shishio from conquering Japan. Of course, being an anime/manga character, and being Kenshin beyond that, he decides it's best for everyone that he just leave, without saying goodbye, definitely without taking anyone along. Except that he does say a farewell to Kaoru. The farewell scene, her tears and the following depression are among the greatest scenes I've ever seen animated. At first, Kaoru can't even bring herself to get out of bed. Finally, Megumi of all people comes to the rescue, pointing out that "At least he said goodbye to you." Stunned, Kaoru realizes that this does in fact mean something. Recovered, she and Yahiko head off for Kyoto; Sano's already set out by Kenshin's overland route, and Megumi, realizing that the better woman won, stays behind and becomes a much more likable person. Stuff happens to Kenshin, but as it's mostly fighting and not really related to Kaoru, it's not important. He does think about her though. Heh. He also acquires Misao, who follows him around demanding to know what he knows about Aoshi, (did I mention Aoshi before? He's an attractive guy that Kenshin defeated who proceeded to become completely obsessive about "being the strongest" for the sake of his men, who died.) In Kyoto, Kaoru bumps into Weasel Girl Misao by accident, and although I don't think they ever establish how VERY much they have in common, they do become friends. They track down Kenshin at Hiko's place, and in my opinion Kenshin and Kaoru have some Moments. Other stuff happens... ::dismissive hand wave:: Kenshin learns some technique or something. I do remember that he was an ADORABLE child, though at around 13 he hit a rough patch. Back to the interesting bits. Kaoru, Yahiko, Misao and the other Kyoto Oniwabanshuu defend the Aoiya from several Jupongatana, and there's one awe-inspiring fight in which Kaoru, working with Misao, manages to defeat Kamatari, Shishio's cool gay guy. The guys fight a lot too. Finally, they get home, reuniting Kenshin with the important character, and things are happy. For a while.