Chapter 4 of The Tale of Genji

Evening Faces
Summer to the tenth month of Genji's 17th year.

On his way to visit Lady Rokujo, Genji hears that his old nursemaid, now a Buddhist nun, may be on her deathbed. He heads off to visit her at the house of Yugao with Koremitsu, her son.
When they get there, the old nun shows more affection for Genji than she does for her natural son.

On his way out, his curiosity is aroused by the possibility of hidden pleasures in the house and he dispatches Koremitsu to investigate. He reports back with the news that To-No-Chujo has been paying visits to the house and that a lady does indeed live at the house of Yugao.
His curiosity peaked more than ever, he dons a disguise and arranges a secret meeting through her maid, Ukon.

The woman of Yugao is very frail and submissive, and Genji immediately recognizes her as one of the women To-No-Chujo had described on the rainy night described in chapter 2. Instead of being annoyed by her gentility as To-No-Chujo was, Genji is attracted by it. In fact he is so taken by her, he plan to make him his own. However Yugao (as she comes to be known) is very frightened by his brashness and rushes off with Ukon to a deserted hideaway. Of course Genji follows.

That night, Genji dreams of a jealous woman who resembles Rokujo, and when he wakes up, sees an apparition by her pillow. He tries to wake her but she is no longer breathing. Panicking, he wakes Koremitsu and Ukon but it is too late, she is dead. Genji is sent home and Koremitsu takes her body to a nunnery for funeral rites.

At home Genji is upset and cannot calm himself. He cannot appear in court because he has been tainted by death. He sets out on horseback to see Yugao's body one last time. On his way home he becomes ill and falls from his horse.

After his recovery he summons Ukon and confirms that Yugao was in fact To-No-Chujo's mistress and that she had a son by him. He asks Ukon to find the son as he plans to keep him under his protection. He also decides to retain Ukon out of sympathy.