One day, while playing the online game Elder Tales, 30,000 players suddenly find themselves trapped in another world. There, eight-year veteran gamer Shiroe also gets left behind. The trapped players are still alive, but they remain in combat with the monsters. The players don't understand what has happened to them, and they flee to Akiba, the largest city in Tokyo, where they are thrown into chaos. Once proud of his loner lifestyle, Shiroe forms a guild called Log Horizon with his old friend Naotsugu, female assassin Akatsuki and others.
Princess Rayneshia has resided in Akiba for a while now, getting along with the people in town. One day, she receives a visit from her mother Sarariya and is told that she will be engaged soon to the head of a powerful noble family.
Touri of the Saiguu Family, Princess Rayneshia's husband-to-be, sends a messenger to let her know the preparations are in place for their marriage. Meanwhile, Eins declares that Honesty will secede from the Round Table Conference.
When Shiroe goes to see Eins to discuss the future of Akiba, he finds the head of the Saiguu Family was also waiting for him. They ask Shiroe to help them with the Akiba Government. The answer Shiroe reaches is…
The residents of Akiba are notified of the election. Both parties campaign to gain their support. Meanwhile, Rayneshia needs to face her mother to get permission in order to be part of the New Round Table Conference.
Election day has finally come. Standing in front of Adventurers and the People of the Land, both Eins and Rayneshia give sincere speeches. Votes are cast and starting to be counted. What will the result be?
Krusty has something to tell Shiroe. In his message, he recounts what happened to him after he disappeared, as well as his encounters with Enchantress Youren and the Ancient hero Elias Hackblade.
Krusty and Kanami's group face their enemies in Sirius Grotto. During the battle, the truth about Enchantress Youren comes to light. Will Krusty be able to overcome his curse?
At the Round Table Conference gathering, people notice that Rayneshia seems to be preoccupied by something. Meanwhile, on their way back from training, Toya and the others find Ancient sisters.
Minori finally gets to go shopping alone with Shiroe. While exploring the store, she learns a lot about items and raids. Meanwhile, Shiroe checks in with Isaac to see if he's noticed anything unusual.
One morning, the Adventurers wake up and realize that the Akiba they're currently in isn't the Akiba they know. With reduced levels, they start to feel helpless, but Shiroe notices there's still hope.
The young Adventurers challenge the raid. Without any adults' help, they must defeat the enemies and bring back normality to Akiba. Can they beat this raid by themselves?
The young Adventurers fell to despair by Ereinus. However, Akatsuki, Lelia, and Litka's fighting spirit reinvigorates the team’s morale. Under Minori's command, they stand against the Genius once again.