The Bridge of Khazad-Dûm - The Fellowship stands in silence at Balin's tomb, and then Gandalf finds a record book describing a terrible battle ending in the slaughter of the Dwarves living in the mines. "Drums, drums in the deep," reads the record book.

As they consider the meaning of the writing, they hear a "doom, doom" coming from the mines: drums in the deep. Soon, Orcs appear, and with them, a cave-troll. The Fellowship defend themselves, and in the ensuing battle, Frodo is struck by an Orc-chieftain's spear, collapsing as though dead. He surprises the others by speaking. Gandalf tries to hold off the enemy forces with magic, but a powerful magic of unknown source resists him. They all flee, making for the gates leading out of Moria. They come to a deep chasm crossed by a narrow bridge, which is the Bridge of Khazad-dûm.

At the chasm, Gandalf faces a Balrog—a fearsome creature made seemingly of flame. Realizing the Balrog is a powerful enemy, Gandalf tells the others to flee, and faces the Balrog alone, saying, "You cannot pass." Gandalf's magic breaks the bridge, and the Balrog falls into the chasm, but at the last minute the Balrog grasps Gandalf and causes him to fall as well. Weeping and stumbling, the remaining members of the Fellowship escape Moria and enter again into the sunlight.