While at the Castle of Corbin, Lancelot is plagued by depression—he does not want to quest or do anything. One evening, particularly depressed, Lancelot gets very drunk with the castle's butler who plies Lancelot with more and more alcohol. Suddenly, the butler announces a message has arrived for Lancelot: it says that Guenever is at a castle five miles away and wants to see him.
Lancelot is depressed because he knows he is in love with Guenever, but also loves Arthur deeply and does not know what he can possibly do. This depression weakens him, exposing him to the sly seductions of Elaine.
The next morning, Lancelot wakes up heavy-headed, confused and in a strange room. The body lying next to him is not that of Guenever, but Elaine. Lancelot is shocked and saddened, but also furious and threatens to kill Elaine: Lancelot had cherished his virginity as though it were the source of his power, and feels that now his strength has been taken from him. Elaine, it turns out, had tricked Lancelot into bed because she is in love with him. Disgusted, Lancelot leaves the castle and returns to Camelot.
By losing his virginity, Lancelot believes he has lost all his knightly skill and power. It is as if his virginity has kept his fundamental sense of impurity at bay. However, once he has lost his virginity, this leaves him free to pursue Guenever—because he feels he no longer has any purity to protect.