BT and Sora suspect that Tsukasa is somehow connected to a very important artifact, the Key of the Twilight.

Mimiru encounters a novice player and offers her guidance in The World. This new relationship helps Mimiru uncover her own motivation for playing.

Tsukasa stumbles upon Aura, an advanced AI, that is being held captive.

As the battle intensifies, the group seeks shelter in the Cathedral. Morganna summons Guardians to do her bidding.