Armed with a large sniper rifle, Hecate II, the young girl Sinon is making a name for herself as the No. 1 sniper in GGO. When her squadron ambushes another squadron, she succeeds in taking out her first target. But when she takes aim at her second target, a robed “Behemoth,” he dodges the bullet.

Kirito and the others are tasked with subjugating the Frost King Thrymr, and a quest to recover Excalibur. It's Yui's guess that this isn't a quest planned by the game admins, but something automatically generated by the system. And if that's the case…

A few days have passed since Yuuki suddenly disappeared from in front of Asuna, and she still hasn’t logged in to ALO. Later, Asuna meets Kazuto on the school roof, where he hands her a note and tells her Yuuki might be at the location written on it.