The Day Before

The Day Before (ザ・デイ・ビフォア) is a side story on Kirito's and Asuna's day after Kirito proposed to Asuna.

Summary
Kirito had just proposed to Asuna the previous day, and she accepted the proposal. Kirito tried to figure out what marriage meant for him now as SAO is an MMO game, before actually going through with it. They visited the 22nd Floor looking for a house Kirito had found when the front lines were there, but when they arrived, they found that the house had disappeared.

They tried to figure out what happened with the house, and in the process they found the house flying in mid air, with someone trapped inside. They approached the house and found a dog named Toto, which Asuna immediately took a liking to, but Kirito was wary about it. When Asuna tried to pet it, the dog made them start a quest, and both were sent flying to the house, where they found Argo. Argo explained that she had been trapped for two days in the house because she started the quest but couldn't continue. Kirito and Asuna figured out that the key to continuing the quest was the dog: Toto, and that Argo was afraid of dogs so she ran away from it, entered the house and the event started, but because the dog didn't come with her, she couldn't continue.

With Toto now with them, the actual quest began, taking them to an isolated part of the 22nd Floor, where they met some monsters acting as NPCs and identifying themselves as a lion, a scarecrow and a tin man. They explained that the Witch of the West took their friend, along with their courage, brain, and heart, respectively, and asked them for help. Asuna and Argo immediately figured out that it was a quest based on the Wizard of Oz story, but Kirito didn't know anything about it, so, despite his doubts, he decided to follow Asuna and Argo.

They arrived at a big castle, where the boss should've been. Despite Kirito's and Argo's objections, Asuna brought the dog with them. Taking advantage of their higher level and Argo's agility, they easily arrived at the boss room, where a girl was trapped. An event started and all of them were paralyzed as part of the event, but also as part of the event, they were freed by the lion roaring. Then, they attacked the Witch of the West, but did not deal much damage. Asuna let Toto run free, who made the Witch fall into the pot, thus defeating her and they then proceeded to liberate Dorothy. On their way back, Asuna explained the story of the Wizard of Oz to Kirito and he understood that the lion, scarecrow, and tin man had what they needed inside them, and he also had the answer he had been looking for.

Before leaving, Argo gave her thanks to them and promised to keep the secret of their engagement. After Argo left with the stealth of a ninja, Asuna started giggling, thus loosening the tension. Feeling that the last thorn in his chest had disappeared, Kirito navigated his menu and sent a marriage request to Asuna, who then happily pressed the "Yes" button.