Collum wakes hungover at Camelot and trains in the magnificent yard, savoring the dream of being a knight. Bedivere and Dinadan summon him to Camelot's vast armory under the pretense of fitting him with new armor. Instead, the knights ambush him, gag him, bind him, and seal him in a coffin while listing his lies: his false father, the stolen armor, his ties to Morgan, his hidden origins. They drop the coffin down the castle well.

Collum breaks free underwater and surfaces on a beach near Astolat, where Lord Numerius takes him in. He becomes the Knight of the Fountain, guarding a sacred grove with a marble statue of a sword-bearing maiden, defeating challengers and resigning himself to a quieter life away from Camelot's expectations.

A formidable knight bearing a blue rooster shield defeats and abandons him in a desert. There Collum saves a black lion from a serpent; the lion becomes his companion. He endures cyclical adventures, a cursed invisibility ring, rescues, and a chance reunion with Blue Rooster, who confesses mistaken identity. Collum drifts as a mercenary in the Frankish kingdoms, feeling life passing meaninglessly.

Glimpsing a girl who reminds him of someone, he resolves to return to Britain. En route, he agrees to slay a dragon plaguing a lord's land. In the dragon's hoard he finds an ancient sword, but flees in terror when the beast attacks. The lion sacrifices itself covering his retreat. Emerging from the cave, Collum finds himself impossibly back at Astolat, with Lord Numerius and the surviving lion waiting.

Numerius offers Collum his old post, naming his failures: oath-breaker, coward, liar, bastard. Collum accepts the truth but refuses to stay, declaring he knows where he belongs. The price is everything: he pays the statue with Nimue's silver shilling. The fountain drains into a well. A voice—the lion's—tells him Mordred alone did not doom Arthur, and that to rebuild Camelot he must learn why it fell. Collum leaps in, swims through a submerged Roman pipe nearly drowning, and surfaces in a chapel surrounded by Bedivere, Dinadan, Dagonet, Palomides, and Constantine, who welcome him as a true knight of the Round Table. The whole ordeal was an initiation ritual.