The setting is the coroner’s office in Cataraqui County, New York. The coroner, Fred Heit, is informed by telephone that it appears a husband and wife have been drowned in Big Bittern Lake. The woman’s body has been found but not the man’s. In the pocket of the coat the woman left at the inn is a letter addressed to Mrs. Titus Alden. Heit and his assistant Earl Newcomb head for the lake.
Roberta’s face is bruised, which immediately arouses suspicions. Suspicions increase when it is discovered that the man supposedly drowned used different names when he registered at Grass Lake and then at Big Bittern, and also that he took his bag with him when Roberta left hers behind at the lodge. Roberta’s letter, written from Grass Lake, reveals that she had gone there to be married. The coroner thinks this will make a good case for his friend Orville W. Mason, and will enable Mason to win election to a judgeship in the fall. Heit also learns that two men and a boy report encountering a young man on the night in question, walking southward about three miles from Big Bittern toward Three Mile Bay. Their description of him matches the description given of Clyde by the local innkeepers.
Heit goes to Mason and reports the details of what he regards as a murder case. He reports that the captain of a steamboat saw the young man in question on the boat from Three Mile Bay to Sharon. Mason believes this is a good case that will help his career.
That same afternoon, Mason drives to the Alden family home, where he informs Titus of his daughter’s death, believed to be a murder. Titus is grief-stricken and demands revenge against Roberta’s killer. Mrs. Alden is informed of the news and collapses. A doctor is sent for, and the neighbors gather. The woman recovers sufficiently to tell Mason that Roberta had mentioned the name of a Clyde Griffiths. Mason realizes that Griffiths has the same initials as the mysterious Clifford Golden and Carl Graham (the two names used by Clyde to register at the inns). Mason then learns from the post office that Roberta had been writing to Clyde Griffiths. He eagerly looks forward to prosecuting the case.
Mason finds in Roberta’s bag a Christmas gift from Clyde, with his first name signed. Mason also suspects that Roberta may have been pregnant, and he orders an autopsy. He acquires a search warrant and searches Clyde’s room (Clyde is away with a camping party at Bear Lake), where he finds in Clyde’s trunk letters from Sondra, his mother, and Roberta. As he reads them he understands the situation; Clyde betrayed Roberta for a girl in a higher social position. Mason makes some calls, ordering the arrest of Clyde for murder.
This chapter is a flashback to Clyde’s actions since Roberta’s death. He made his way from the scene of the crime to the Cranstons at their lodge by the lake in a state of extreme distress. He believes he is not guilty of murder, but who would believe his story? He was terrified by his encounter with the hunters as he walked to Three Mile Bay. When he reached the bay he waited in the woods until morning, and then took the boat to Sharon, where he called the Cranstons and they sent a car to pick him up. He pretended he had just arrived on the train from Albany. He was scared that he would be detected and that there may already be people looking for him.
Clyde reveals himself in these chapters to be a very bad plotter. He has left a trail of incriminating evidence that the authorities find almost immediately. Other than the fact that Roberta is indeed dead, as he wished her to be, every other aspect of his plan is totally inept. There seems to be no way in which he is going to be able to escape the reach of the law, and he is also unfortunate enough to attract the attention of a zealous and formidable district attorney. In accordance with his deterministic philosophy Dreiser explains the motivations of the district attorney, Orville Mason, in terms of his early experiences in life. He was raised in poverty and neglected, “causing him in his later and somewhat more successful years to look on those with whom life had dealt more kindly as too favorably treated” (chapter III). It is this that gives Mason his driving ambition. It is also Mason’s “youthful sexual deprivations” that has given him what Dreiser calls rather oddly a “psychic sex scar.” He means that Mason has a kind of repressed sexuality that leads him to a keen and perhaps unsavory interest in the sexual aspects of the case: the fact that Roberta was involved in an illicit affair and was pregnant. Mason will now become a dominating force in the novel, driven by political ambition and with an instinctive revulsion against the defendant.