Aubrey returns to London and is amazed when Ruthven appears shortly thereafter, alive and well. Ruthven reminds Aubrey of his oath to keep his death a secret. Ruthven then begins to seduce Aubrey's sister while Aubrey, helpless to protect his sister, has a nervous breakdown. Ruthven and Aubrey's sister are engaged to marry on the day the oath ends. Just before he dies, Aubrey writes a letter to his sister revealing Ruthven's history, but it does not arrive in time. Ruthven marries Aubrey's sister. On the wedding night, she is discovered dead, drained of her blood â and Ruthven has vanished.