Tsukasa, a Wavemaster-class character in the online game "The World", finds himself unable to exit the game. While meeting with fellow players, he attracts the attention of a conflict mediation guild, the Crimson Knights.
Subaru, the leader of the Crimson Knights guild, meets with Mimiru, Bear, BT and Sora to discuss Tsukasa's activities and a possible connection with a rumored all-powerful item: the Key of the Twilight.
Despite restrictions placed upon his character, Tsukasa has been logged into the game for 10 days straight, and rumors fly about a player-killing monster running loose. At Sora's suggestion, Subaru and the Knights declare Tsukasa a wanted player throughout "The World".
Mimiru encounters a weak yet adventurous newbie player, A-20, who goads Mimiru into taking her into a challenging dungeon for unknown reasons. After a verbal scuffle, Mimiru ruminates upon her own motivation for playing "The World".
Mimiru, after careful consideration, resolves to do anything she can to meet Tsukasa again and be near him as much as possible. BT and Crim discuss a partnership to gather information on the Key of the Twilight.
Bear joins Mimiru for an event held in the Dungeon of Nankoflak, a newly reopened dungeon known for giving rise to many a legend in the past. But Mimiru isn't there for the experience points or the treasure, but rather memories of one of her first experiences in The World, and the players she met there.