Outside, Cedric tells Locksley and the Black Knight about Ulrica's promise. They need to storm the castle--Athelstane, Lady Rowena, and poor Wamba are in danger! The Friar agrees that action is necessary. They take the outerwork, and in time assemble a raft with which to cross the moat. When complete, the assault continues, with the poorly- armored Cedric helping to lead the way inside. While the outlaws try to break down the door, Ulrica raises the flag, but De Bracy begins to push at heavy stones above, making the work below very dangerous. But Bois-Guilbert tells him all is lost, the castle is on fire. They plan to rush out the door, pushing everyone aside. They will abandon the castle.
De Bracy and the Black Knight fight outside. When De Bracy is struck down, he agrees to surrender only if he may know the Black Knight's identity, which the Knight whispers to him. He then warns the Knight that Ivanhoe languishes above, and will surely perish if not rescued. Up in the tower, Rebecca and Ivanhoe notice the fire but, despite his urging, Rebecca refuses to leave her patient. Suddenly, the Templar enters, and carries her off. Ivanhoe's yelling draws in the Black Knight, who takes Ivanhoe, despite his demands the Knight save Rebecca, or Rowena, or Cedric instead. But Cedric finds Rowena and frees her, and Wamba frees himself and Athelstane.
The Templar and Rebecca are in the castle court. Mistaking her for Rowena, Athelstane attacks, and receives a violent blow to the head. Realizing he cannot save de Bracy, Bois-Guilbert rides off.
Up in the castle, Ulrica, crazy and violent, sings wicked hymns. Flames engulf the castle, whose turrets begin to crumble and fall. She can be seen from below, until the tower crashes, killing her and Front-de-Boeuf. Locksley cheers the castle's demise, and tells his men to collect their spoils and bring them to the forest for equal division among the men.
