Log Horizon (Light Novel)

The Log Horizon light novel series was first released in web format by Mamare Touno. Seven volumes have subsequently been published, with an eighth to be released on September 29, 2014. Yen Press has licensed the series for its light novel publishing section, Yen On. The first volume is slated for a April 2015 release.

The Catastrophe arc
On May 3, 2018, thirty thousand Japanese players of the popular MMORPG Elder Tale found themselves trapped in -- or a world startlingly similar to -- the game. A reclusive yet well-known Enchanter, Shiroe, is among them. After quickly contacting his long-time in-game friend Naotsugu, a Guardian, the two of them wander about the streets of Akihabara, their player city. While assessing the situation, they are found by Shiroe's friends, a bubbly female Cleric named Maryelle and the relatively more composed Henrietta, whom they exchange information with. After some days of exploration, they meet yet another of Shiroe's companions, a stoic Assassin named Akatsuki. "He" turns out to be a "she," trapped in her initially-male avatar, saved from her plight thanks to Shiroe's possession of a rare appearance-changing potion. Because of this, she dedicates herself to him as her "ninja," and together, the three work on honing their fighting skills as they witness the deteriorating situation in the city.

Saving Serara arc
Several days after the Catastrophe, and having adjusted to fighting in this new world, Shiroe, Naotsugu, and Akatsuki learn from Maryelle and Henrietta that one of the Crescent Moon Alliance's members, a low-level Druid named Serara, was trapped in another player city called Susukino, having gone there just before the Catastrophe struck to complete the quest. Now, with the transport gates down, she has no means of escaping Susukino's ruling guild Brigandia, whose leader had an interest in capturing her. Although she had been saved by a benevolent Werecat Swashbuckler, they wanted to get her back into the relative safety of Akiba. Knowing full well that the Crescent Moon Alliance wouldn't be able to get to Susukino quickly enough, Shiroe's Party offers to help and make the journey up themselves. When they arrive at Susukino, they discover that Serara's benefactor was in fact Nyanta, an old friend of Shiroe and Naotsugu's. Together, they defeat Demiqas and return back to Akiba, but not before learning from Nyanta the secret to flavorful food.

Round Table Alliance arc
Upon returning to Akiba, Shiroe is alarmed by Maryelle's explanation of the changes in Akiba since he had left. The major guilds ruled the city, with the large battle guilds pressuring smaller guilds into either disbanding or joining them and having priority in the market, leaving nothing for the small-and-middle-sized guilds. Even worse, rumors of a malevolent guild called Hamelin have been floating around, ones that say that this guild has essentially enslaved younger players after tricking them in order to make a profit off of their EXP Pots, which large battle guilds are purchasing. Realizing that two kids he had been mentoring, Minori and Tohya, had been taken in by this guild, Shiroe decides to step up and do something about it after some encouragement from Nyanta. With the rest of his party, sans Serara who returned to her guild, he forms Log Horizon and, with the Crescent Moon Alliance, begins to take action.

Route 43 arc
This arc covers the material found in Log Horizon 8: The Sparrows Stretch Their Wings.

Go East! arc
This arc covers the material found in Log Horizon 9: Kanami, Go! East! and Log Horizon 11.

Noosphere arc
This arc covers the material found in Log Horizon 10: Homesteading the Noosphere.

Resources
There are some notable differences between the web and novel versions. As of the moment, the web version is still being updated. However, translation projects for the novels appear to be focused on the published versions.

Official Sites:
 * mamare.net: Mamare's official site (currently down)
 * Web novel: A site where Mamare publishes the initial version of the Log Horizon chapters. (Currently on volume 8.)

Translation Projects:
 * skythewood: He has completed everything up to volume 7, but will not continue with volume 8's translation because Yen Press licensed the series.
 * iforgot: An independent project starting from Volume 1. More sporadic updates.