: Thrym, the King of the Frost Giants, threw Excalibur into Urðr's Spring, severing the World Tree's connection to Jötunheimr and turning it into a wasteland.
The episode begins on December 28, 2025, with Suguha showing Kazuto (Kirito) a news article about the discovery of the legendary in ALO. This triggers a flashback to when Kirito and Leafa first discovered the sword months earlier while trapped in Jötunheimr , a frozen underworld beneath ALO. During that time, they rescued a beast-class evil god they named Tonkii , who showed them the sword's location in an ice dungeon. Sword Art Online II Episode 15
: Thrym promised Excalibur to players who help him slaughter the beast-class monsters, but he intends to give them a fake sword. : Thrym, the King of the Frost Giants,