Persuaded by Venn to forget her pride and call on her son, Mrs. Yeobright starts the long walk to his house on a hot August day. She sees Wildeve admitted by Eustacia before she can get there; when she knocks on the door, Clym's wife looks out the window but doesn't answer. The older woman tries to walk back home, stops in exhaustion, and is bitten by an adder. She is later discovered by Clym, who has set off for her house to attempt a reconciliation, but even medical attention cannot save her and she dies. Clym blames himself for her death. Eustacia is nearby when Mrs. Yeobright dies but doesn't make an appearance; she has accidentally encountered Wildeve, who has lately come into an inheritance.
Clym for some time is ill and irrational because of his mother's death. His constant blaming of himself exhausts Eustacia, and she tries to find consolation in Wildeve. Once back to normal again, Clym sets out to discover what his mother was doing on the heath. From Mrs. Yeobright's handyman, Cantle, from Venn, and a young boy who came across his mother as she tried to get home that day, Clym learns what happened. He accuses Eustacia of cruelty to his mother. When Clym adds the charge of deception of himself as a husband, the relationship between him and Eustacia is effectively over. She leaves his house to return to Captain Vye's.
At her grandfather's, Eustacia doesn't know how to occupy herself and once even thinks of suicide. A bonfire is lit for her when the Fifth of November comes, an inadvertent signal to Wildeve, who offers to help Eustacia get away from the heath to Paris. On Thomasin's advice, Clym, now moved back to his mother's house, writes to ask his wife to return to him.
