Story by Ryukishi07; Art by En Kito. Released in Japan as "Higurashi no Naku Koro ni: Onisarashi-hen" by Kadokawa Shoten, serialized in the magazine Comp Ace. Released in North America by Yen Press.
You would think, having read two of the four Eye-Opening Arc volumes last month, that Volume 13 would be the third in that sequence. But you would be wrong! Instead, Yen is publishing a complete-in-one-omnibus edition of a side story that, like Beyond Midnight, was first published as a manga rather than adapted from a game. In fact, this adaptation proved so popular with the creator that he later adapted it into a game on his own. It came out relatively early in the series, manga-wise - the first chapters were published about the same time as the first two Higurashi Arcs proper were being published by Square Enix. This one is done by another company, Kadokawa, which is far more media/franchise oriented (and given the other company is Squeenix, that's saying a lot), and ran in their 'otaku-oriented' magazine Comp Ace.
The story itself takes place in a city, making a refreshing change from the small-town life of the previous books. Natsumi and her family have moved from Hinamizawa to a more urban area, and she's settled in and made good friends. There's even a boy she secretly likes... and he just confessed to her! What's a cute girl to do? ... oh right, this is a Higurashi book. Don't expect shoujo hijinks here, folks. Instead, we see Natsumi worry about her grandmother, who feels they never should have moved away and worries that Oyashiro-sama will curse them.
As with the last manga-only arc, this is only tangentially related to the main action. Near the beginning, we hear news of the Great Hinamizawa disaster, and as time goes by, the survivors who had moved away before it happened start to behave very oddly. Things are not helped by the arrival of Ooishi and Akasaka, who merely want to ask Natsumi a few questions. And then their house gets covered in paper talismans, and the grandmother starts acting very strange...
There's some similarity between this arc and the first in the series, Abducted by Demons. Natsumi's slow descent into paranoia and mistrust is really disturbing, especially since she keeps insisting throughout that she's doing things for her family. Unfortunately, with her first "YOU'RE LYING!", the Higurashi catch phrase, we get a pretty good idea of what's really going on. But then, unlike the main Higurashi manga series, the mystery is not entirely the point of this one. You're here for psychological horror, and it delivers in spades. There's the creepy back-of-the-neck kind of horror early on, but by midway through we're well into 'how do you like your blood spatters?'.
Unfortunately, there is a big flaw in the series, which is Akira, the male lead. They wanted to make him different from Keiichi (and by extension Satoshi), the males from Higurashi proper. Unfortunately, this means making him passive and hard to read. I understand that this was entirely deliberate (in fact, they lampshade it at the end), but it really didn't work for me, and I found it hard to understand his simple obsession with loving Natsumi no matter what the cost.
The ending is tragic, but not a complete kill-em-all, and the author notes he has hopes the survivors will be able to get beyond it. Still, in the end this is a short, sharp gutpunch in the Higurashi series, showing how the events in Hinamizawa can affect even those who are far away. In fact, we'll come back to what happens to those who move away from Hinamizawa in the Atonement Arc this fall. It's not essential to read this if you just want the basic Higurashi story, but it's a good, solid read, provided you don't mind gore (and if you do, how did you get through the other 12 books?)