-Kirito walking towards the tree, with the Christmas Boss descending as per LN chapter. Kirito roars and charges towards Nicholas. Then OP credits.
-Cut to him reminiscing about the Black Cats. First meeting them in a dungeon, explaining how he ended up joining them. He meets Sachi. Leader of Black Cats asks him to train her into a frontline fighter as opposed to spear-wielder.
-a few scenes of them fighting together gaining xp. Then Sachi runs off and we get the following scene in detail:
-Then trap in dungeon Black Cats guild dies one by one, while Kirito watches helplessly. Sachi dies last:
-Next scene with the guild leader jumping off, saying Kirito never should have joined them.
-Cuts to Kirito gearing up, and teleporting to the floor where the boss will come to. Klein's guild catches up to him, but fails to convince Kirito to team up. Other guild shows up, which leads to Klein telling Kirito to go ahead while his guild try and hold them off.
-Back to the scene before the OP. Cue Boss-fight. Ends with Kirito on the verge of death.
-Scene with the revive item. Kirito loses it, resulting in a
skyward scream. Goes back to Klein. hands him the item while Klein begs him to not die, even if he's the last one left in SAO.
-Back in his rented room, Kirito flops down onto his desk as he's tired. Monologues about heading to the 50th floor boss room first thing in the morning, all life gone from his eyes. Sachi's crystal activates, giving him the message. As the song plays, scenes flashes by:
Rudolph, the red-nosed reindeer had a very shiny nose. (Meeting the Black Cats)
All of the other reindeer used to laugh and call him names. (Kirito laughing with the Black Cats, fitting in like a part of the team)
Then one Christmas Eve(Sachi's face in tears, from when she asked if Kirito would run away with her)
Santa came to say: (Sachi's death)
"Rudolph with your nose so bright, won't you guide my sleigh tonight?"
Rudolph who was always crying, started smiling that night. (final cut, Sachi with a radiant smile on her face)
-Episode ends with Sachi thanking Kirito for meeting him and spent their time together. Crystal turns off, then a camera shot of Kirito's head buried deeper into his arms and a line of tears flowing down the side. Cue ED.