Eustacia literally kicks off the novel "anticipating" some sort of change, whether it's dumping Damon, eloping with him, dumping him (for good), or having a romance with the mysterious guy arriving from Paris.
Hardy uses actual dream-like nature imagery to depict these two characters in love and, aside from Clym's conflict with his mother, things seem to be going well for our two lovebirds. But doom is approaching, of course.
Clym and Eustacia have increasing problems in their marriage, Damon arrives on the scene again to further complicate matters, and Mrs. Yeobright's relationship with her son suffers after a series of misunderstandings.
Things go from bad to worse here after Mrs. Yeobright dies tragically and Eustacia is somewhat to blame. After increasingly tense chapters, Clym finally finds out Eustacia's role in Mrs. Yeobright's death and the two have an explosive confrontation that ends with a crushed Eustacia leaving Clym to return to her grandfather.
Eustacia gets increasingly suicidal and she ends up drowning, along with Damon. After this intense tragedy, Thomasin and Clym try to go on with their lives. Thomasin succeeds at this more than Clym does; she ends up marrying Diggory Venn.