The battle between Kirito's party and Thymr intensifies as the King of the Giants's HP is whiddled down by Freyja's magical attacks. With Thymr's attacks becoming stronger, Freyja asks Kirito to find her family's treasure within the mountains of gold in the boss's room, a golden hammer. Taking Leafa's advice, Kirito uses a lightning spell to pinpoint the treasure's location and tosses the unexpectedly heavy hammer to Freyja.
To everyone's surprise (and Klein's chagrin), the hammer causes Frejya to transform into the God of Thunder, Thor: the hammer that Kirito had found was actually the legendary Mjolnir. Thor manages to defeat Thymr, and rewards Klein with a smaller and easily usable version of Mjolnir as a rare drop before departing. The quest still remains incomplete: with time running out, Excalibur must still be claimed.
Thymr's defeat opens the way to the bottom-most level of Thymrheim, where Excalibur is held. Using all of his strength, Kirito manages to free the legendary sword from its plinth, and in doing so, causes the labyrinth to start collapsing. Tonkii comes to rescue the party, but Kirito finds himself unable to store Excalibur in his inventory, and with the sword being too heavy for him to make the jump onto Tonkii's back, he is forced to throw the sword away.
Sinon, however, has one last trick up her sleeve: she casts a spell that transforms an arrow into a tether and manages to land the arrow on the Excalibur, a nigh-impossible shot on a small target from 200 meters away. She successfully retrieves the Excalibur and gives it to Kirito on the condition that he always think of her when he draws it.
With Thymrheim destroyed, the roots of the World Tree touch down on Jotunheimr once again, restoring life to the frozen realm and ending the genocide of Tonkii's kind. Uror appears once again before the party, along with her sisters, to thank Kirito and his party and reward them, with Kirito earning the Excalibur as a rare drop.
Afterwards, in the real world, Kazuto shows off a pet project that he had been working on to Rika and Shino: he installed four cameras in the four corners of Agil's bar, creating a pseudo-3D environment for Yui to navigate in. This is part of a mechatronics project that Kirito is working on, as a means of bridging the gap between the real and virtual worlds and bringing Yui closer to the real world.
