Kimihiro Watanuki is able to see supernatural beings and spirits no one else can see. He involuntarily attracts them but is unable to do much against them. His strong desire to finally be a normal person with a normal life lands him on Yuko's doorstep.
Yuko is a mysterious woman who can grant any wish, but only if she is paid something of equal value. She can help Watanuki stop seeing spirits, but first he has to pay her by working for her as long as it takes to pay off the debt. There is no indication how long this will take, but, despite his complaints, Watanuki doesn't necessarily mind the work he is assigned. His primary duties are to cook for Yuko and those who live with her (a cute black creature called Mokona and possibly two children named Maru and Moru, although I'm not sure those two even eat), provide Yuko with alcohol when she asks for it (which is practically all the time), and clean Yuko's shop. Sometimes Yuko also gives Watanuki odd jobs that have something to do with her clients or the spirit world.
Throughout the course of the season (there is a second season that comes after this, as well as some OVAs), Yuko is visited by various clients. Although most of them are in some way responsible for the problems they find themselves dealing with, Watanuki finds himself more sympathetic to some than others. For instance, Watanuki tries very hard to help one woman whose problems are caused by a bad habit she doesn't even recognize she has. In another episode, Yuko's client is a woman tormented by a murder she committed that she doesn't want anyone to know about.
Some episodes involve supernatural situations, rather than clients visiting Yuko's shop. A couple examples are one episode in which a shy girl who is having trouble confessing her feelings to someone she likes turns out to be a supernatural being, and another episode in which Watanuki and his friend/rival Domeki take part in a procession of supernatural creatures.
I watched this entire 24-episode season/series over the course of four or five days. The Hulu expiration date for all but the first four episodes was coming up, and I wanted to know whether it was worth it to buy the show. Just like I reread books, I rewatch shows, and I wanted to know if this was a show I'd want to rewatch.
Sadly, the answer is no.
I should mention that I've read up to volume 12 of the manga, and I think that spoiled me for the anime. Even though it's been ages since I read any of the manga (my post for volume 12 was published October 23, 2008, and I haven't reread any of the earlier volumes since then), I couldn't help but compare what I remembered about the manga to what I was seeing in the anime. Sometimes my memories were vague enough that there wasn't much for me to compare, but there were some parts of the manga that I loved so much that they seared themselves into my brain, and the anime couldn't quite do those parts justice.
For example, I particularly loved the bit in the manga where Watanuki befriended a woman who had lost her son years ago. Although Watanuki began to see her as a mother figure of sorts, he also realized that being around her was killing him. Despite this realization, he continued to want to see her. I think this was the first time I wanted to own and reread a volume of this manga. I thought this story was a high point in the anime, too - it was one of the few times viewers got to see Watanuki not overreacting in a typical over-the-top anime character kind of way, and the story's aftermath revealed a side to Domeki and Watanuki's relationship that is important for the future (if the anime follows the same path as the manga) and likely made many a fangirl go squee. However, my memories told me that this story was paced a bit better in the manga - like I said, it's been so long since I read the manga, who knows whether my memories are true or not?
Even though it's been a while since I last read the manga, even I noticed that there were quite a few episodes in the anime that were not based on the original manga. One episode was inspired by a story written by NISIOISIN, published in Faust. I remember enjoying the original story, but I felt that the anime adaptation involved too much telling and not enough showing. Other episodes were written just for the anime. And perhaps inspired by too much drinking. I am thinking in particular of the snowball fight episode - if I'm wrong, and that was originally in the manga, then the stupidity of it must have forced me to erase it from my memory.
The problem with some of these filler episodes is that they sometimes broke rules that will be important later on, if the series continues to follow the same path as the manga. The anime hinted about Himawari often enough that I think the next season probably will have the same revelations about her that the manga does - which means the anime has already messed things up. After having Himawari carefully avoid touching Watanuki episode after episode, I believe there's a moment when she touches his arm, or maybe his shoulder. Also, in the snowball fight episode, Amewarashi and Zashikiwarashi take part alongside Himawari without any apparent problems. Even if the anime doesn't go quite the same route as the manga, in the episode with Amewarashi's first appearance she didn't even want to go near Himawari - so how could the snowball fight have been possible?
Aside from all the Himawari stuff, there's also the "Watanuki is never shown eating" thing. I remember that this was considered important in the manga, although I'm not sure I got far enough into the manga to find out why it was important. If the anime doesn't go the same route as the manga, fine. If it does, then I'm pretty sure there's a scene where Watanuki is shown eating ramen. Nitpicky, yes, but it's like getting to the end of The Sixth Sense and then watching the movie again and finding a moment where the guy moves a chair.
I do think I would have liked this series more if I hadn't read the manga first. I thought the series was at its best when it focused on the nature of people and their lives and on the intersection between the human and spirit worlds. I was super-excited to see Zashikiwarashi try to deal with her crush on clueless Watanuki (Zashikiwarashi, Naruto's Hinata, Negima's Nodoka - I'm a fan of that type of character, even though, when taken too far, that kind of character can also make me want to smack them). The series had its bright spots, to be sure.
That said, I'm pretty sure the snowball fight episode would have bothered me, even if I hadn't read the manga.
Overall, this is not a series that screams, "Buy me, you'll want to rewatch me sometime in the future!" I would recommend the manga over the anime, although I think the manga takes longer than it should to get to the point.
For those of you who have heard of the Tsubasa: Reservoir Chronicles and Xxxholic plot crossovers and are concerned you may have to keep track of two series to get the full story, don't worry - the Xxxholic anime (or at least this first season) makes absolutely no mention of any of the events or characters in Tsubasa. I thought this was a bit odd, but I imagine that the crossover must happen in one of the movies or something. For those who are fans of CLAMP's other works, some Legal Drug characters made an appearance, Chi's ears turned up in one episode, and I think I spotted Sakura's scepter/staff thingie - there may have been more references that I missed.
Watch-alikes and Read-alikes:
- Mushi-Shi (anime TV series) - This might be a good one for those who were particular fans of the Xxxholic episodes that focused primarily on the supernatural and featured Yuko at her most mysterious. I still haven't seen much of this series (bad, because I've owned it for a while now), but what I've seen focuses on a mysterious traveling scholar who studies beings called Mushi, creatures most people can't even see. The anime is based on a manga series, which I haven't read.
- Hell Girl (anime TV series) - I haven't seen this one, but, from what I've heard about it, it may be a good fit for those who'd like more stories about the dark side of human beings. In this series, those seeking revenge against someone can get that revenge via a form on a website that can only be accessed at midnight. The Hell Girl will carry out that revenge, but a price must be paid. This series is more serious that Xxxholic.
- Sayonara Zetsubou-sensei (anime TV series) - If Watanuki had Himawari taken away from him, and if he were then made to star in a dark comedy, he might become something like the main character of this series. Something about Xxxholic's visual style, in addition to Watanuki's overreaction to just about everything, reminded me of this series. Approach this one with caution - it has very dark humor and panders to the crowd that likes sexualized high school girls. That said, I still enjoyed the series, for the most part. It stars a very, very depressed high school teacher whose main goal is to kill himself. Each of his students have over-the-top and often strange identifying characteristics, like the girl who is unbelievably optimistic, or the girl who gets mistaken for a victim of domestic violence because she loves pulling animal tails and works at a zoo. Again, this one is based on a manga series, but I haven't read it.
- Bakemonogatari (anime TV series) - I haven't seen this one yet (I don't think it's licensed in the US yet, although with as many US fans as it already has, I'm sure companies are at least looking into it), but, from what I've heard of it, this might be a good match for those who'd like something else with supernatural beings and brief, fairly self-contained stories. This one's on my "to watch" list, due to some incredibly lovely and awesome clips I've seen.
- Pet Shop of Horrors (manga) by Matsuri Akino - I haven't seen the anime yet, but the manga, in my opinion, is the same as Xxxholic, in that they both have lots of self-contained stories that deal with human nature and/or the supernatural, but Pet Shop of Horrors is cheesier and less ambitious. This series focuses on a mysterious pet shop where people can possibly find the pets of their dreams - but only so long as they follow the sometimes strange care instructions they are given. For some of the pets, it's similar to "don't feed the gremlins after midnight."