When Adam notices that Hetty's friendly attitude toward him does not change, he concludes that there had really been nothing serious between Arthur and her. He proposes to her, she accepts, and the wedding is set for the following spring. Adam is deliriously happy and spends the next three months making preparations. Hetty, meanwhile, has fits of depression and contemplates suicide; she is pregnant by Arthur. She decides to run away and go to Arthur; telling the Poysers that she is going to visit Dinah in Snowfield for a week or two, she sets out.
After traveling for seven days, Hetty arrives sick, exhausted, and penniless, at Windsor. Here she is befriended by an innkeeper and his wife who inform her that Arthur's regiment has left for Ireland. Hetty faints in despair, but the next day her courage revives, she gets some money from the innkeeper in exchange for the jewelry Arthur had given her, and she heads back north, intending to go to Dinah in Snowfield. After five days of traveling, though, her spirits give out, and she leaves her coach and wanders out into the open fields. She spends part of a night by a pond but can't summon the courage to kill herself and so resumes her journey on foot towards Stonyshire.
When Hetty does not return in the expected time, Adam decides to go to Snowfield and bring her back. He discovers, of course, that she has never been there, and he tries to trace her but to no avail. Realizing that she has probably gone to Arthur, he resolves to go to Ireland. He stops at the parsonage to tell Mr. Irwine his plans and is shocked to learn that Hetty is in prison in Stoniton for the murder of her baby. He and Mr. Irwine go to Stoniton; Mr. Irwine returns the next day to break the bad news to the Poysers, while Adam rents a room and stays. Meanwhile, Arthur's grandfather has died and Arthur has set out for home from Ireland.
As the trial begins, Adam sits in his room in despair. Mr. Irwine and Bartle Massey (who has come to stay with Adam) bring news of how the trial is progressing; Hetty's guilt seems certain, though Adam refuses to believe it. Finally he goes to the courtroom himself. Two witnesses give evidence against Hetty, the jury returns the verdict of guilty, and the judge pronounces the death sentence. Meanwhile, Arthur has returned home, found a note from Mr. Irwine explaining the situation, and left for Stoniton.
