Launcelot enters Castle Corbin and cautiously picks his way forward. He’s ready for anything, but instead of anything, he encounters nothing. A whole series of empty rooms, doors hanging open, nothing stopping him from penetrating to the very center of the castle. And there, in the center, he finds a chamber whereof the door was shut, and he set his hand thereto to have opened it, but he might not. Then he enforce[s] him mickle to undo the door, which is to say, he tries really hard you guys, but he just can’t shove it open!
From the other side of the door he hears yet another of these disembodied angelic voices. “Joy and honour to the Father of Heaven,” the voice sings.
Launcelot panics, drops to his knees and prays for guidance. He admits, in this prayer, that he’s done all kinds of terrible things in the past, but he’s working hard to get better, and he would really appreciate it if God would help him out as regards this door. If he can’t go in and actually acheieve the Grail — and maybe that’s too much to ask, Launcelot realizes — maybe God could just let him get a little peek?
Miraculously, the door flies open! And from out that central chamber comes a whoosh of air and a great clearness, with the whole castle lighting up. Launcelot figures this is his prayer being answered, and stands to go inside.
“Flee, Launcelot, and enter not, for thou oughtest not to do it; and if thou enter thou shalt for-think it,” says the disembodied angelic voice.
So Launcelot hesitates, and he peers into the chamber from the doorway. Inside there’s a big silver table, with the Grail on it, under a red velvet coverlet. The room is crowded with angelic figures, holding candles and crosses, and also Nacien is there.
Launcelot stands transfixed and watches Nacien and the angels inside. Nacien performs Mass and there’s this whole laser light show thing happening: images of three men, the younger of the three sitting on the shoulders of the other two. Or maybe it’s, like, a holographic image of Galahad (let’s not play games, obviously it’s Galahad) and Nacien somehow plucks the image out of the air? It’s vaguely worded. It might even be that Malory is trying to say Percivale, Bors, and Galahad are up in the rafters over Nacien’s head, and Percivale and Bors lower Galahad to within Nacien’s arms-reach.
In any case, Launcelot is amazed by the incredible magical holiness of what he sees! But then, either Galahad or the holographic image of Galahad or whatever, it proves to be just too much for Nacien to handle, and Nacien starts to collapse, right there! And all the angels are just standing by watching!
Launcelot dashes into the Grail chamber to help Nacien, muttering a quick apology to God as he goes (“Fair Father Jesu Christ, ne take it for no sin though I help the good man which hath great need of help”).
As soon as he’s all the way in the room, he bursts into flame and collapses.
Launcelot lies there, immolating, for an indeterminate time, and then the angels pick him up and toss him out of the Grail chamber and close the door.
In the morning, the various mortal inhabitants of Castle Corbin find his body, and argue about whether he’s dead or not. They eventually settle on merely horribly injured, and stick him in a bed, where he lies comatose for a month.