Walter's conversation with Mrs. Clements gives him the opportunity to learn more about Anne's history. Mrs. Clements first met Mr. and Mrs. Catherick when she moved to Old Welmingham after her marriage. Mr. Catherick was the parish clerk and before her marriage, Mrs. Catherick had been a lady's maid in a wealthy family. As a result, she was somewhat proud, and disrespectful to her husband, and Mrs. Clements took a dislike to her. A few months after their arrival, and shortly before Mrs. Catherick was due to give birth, Sir Percival arrived in the neighborhood. Mr. Catherick confided to Mrs. Clements that he had discovered valuable items in his wife's room, which must have been given to her by someone wealthy. This discovery, plus rumors of her meeting Sir Percival privately, left Mr. Catherick concerned that his wife may have had an affair and married him only once she found out she was pregnant. Mrs. Clements told him to do nothing immediately, and to try to find out more information.
Two days later, Mr. Catherick caught his wife and Sir Percival whispering together, flew into a rage, and attacked Sir Percival. He lost the fight, and disappeared from the village that very night, ashamed and angry. Sir Percival also left quickly, but Mrs. Catherick defiantly stayed on, insisting that she was a faithful wife who had done nothing wrong. She refused her husband's offer of an allowance, so it is not clear where her income comes from, though Mrs. Clements suspects that Sir Percival supports her financially. Walter is puzzled, because he does not see how the possibility of Sir Percival being Anne's father could be the secret—it had already been public enough to cause a scandal. He also wonders why Mrs. Catherick would stay in the village knowing that her reputation was ruined.
Walter is able to feel certain that Anne's father was not Mr. Catherick, as the dates of the pregnancy and wedding do not align. According to Mrs. Clements, Anne did not resemble either Percival or her mother, which makes him wonder if another man could be the father. He learns that prior to her marriage, Mrs. Catherick worked in the household of a man named Major Donthorne. Mrs. Clements also explains that she frequently cared for Anne during her childhood, since Mrs. Catherick often seemed to despise her, although she would occasionally display periods of stronger interest. When Anne was around 10, she and her mother went to Limmeridge House, during which time Mrs. Clements lost her husband. When they came back, Mrs. Clements wanted to move to London and asked if Anne could come with her. Mrs. Catherick did not allow it, and after Mrs. Clements moved away, she did not see Anne again until Anne escaped from the madhouse.
Mrs. Clements has also heard about the secret from Anne, but never learned what it was. She suspects Anne may not have actually known it either, which is an idea Walter has also started to suspect. Before he leaves, he tells Mrs. Clements that Anne has died, but that she was well taken care of and given a good funeral. He also asks for Mrs. Catherick's address so that he can visit her, despite Mrs. Clements warning him not to do so. Within a few days, Walter has gone to meet Mrs. Catherick and tells her that Anne is dead. Mrs. Catherick shows very little interest or reaction, so Walter explains that Anne's death has caused distress for someone else due to the interference of Sir Percival.
Walter explains that he knows something suspicious about the time when Sir Percival was interacting with her before Anne's birth, and that he wants her to give him any information that will help bring him to justice. Mrs. Catherick angrily defends how hard she has worked to restore her reputation after the scandal, and refuses to help him, even though she doesn't deny that Sir Percival is also her enemy. Walter makes it clear that he doesn't believe she and Sir Percival had an affair, but Mrs. Catherick stubbornly refuses to tell him anything. He decides to go to the church in Old Wilmingham where they had been caught meeting, since she seemed to have a strong reaction to him knowing the specifics of the place.
Walter's investigations reach back not just into the events surrounding the scheme, but over decades. The information about Percival's history with Mrs. Catherick offers one possible answer to the secret: that Percival is Anne's father. However, Walter finds this answer unsatisfying and the fact that he does so sheds light on the gendered and social dynamics of the era. While it was certainly somewhat scandalous, it was by no means unheard of for wealthy titled men like Sir Percival to occasionally father illegitimate children, especially with working-class women. Typically the father would provide financial support in exchange for discretion on the part of the mother, and such an event would be unlikely to have serious consequences for his life. As Walter immediately notes, it doesn't make sense that Percival would be particularly distressed at the news of an illegitimate child coming to light, because this would not ruin his life the way he seems to think that the secret would.
For Mrs. Catherick, however, the impact of the scandal was very different. Walter's second clue that there must be more to the story is the fact that Mrs. Catherick chose to keep living in the same town. Walter knows that as a woman implicated in adultery and premarital sex, her reputation would have been ruined and she would have been shunned by the community. He accepts without question the way in which the same events would have had such a different impact on a man and a woman.
While Walter has not yet learned the nature of the secret, he has come to suspect that Anne may not have actually known it either. Mrs. Clements shares the same perspective. This idea is interesting because it suggests that Anne was both more cunning, and yet also more unaware, than we had thought. She was able to successfully give the impression of having knowledge she didn't actually possess, but she did so so successfully that she put herself in danger. Had Sir Percival thought of her as a harmless idiot, he would have had no reason to be afraid of her, and would not have tried to imprison her in the asylum. This paranoia about women knowing secrets they don't actually know had already come to light when he became obsessed with the idea of Laura having learned the secret. It seems that Percival, despite the power that his class and gender give him, is terrified by the idea of being undermined by a woman.
Walter's visit with Mrs. Catherick gives the strongest example of someone failing to protect an individual under their care. Mrs. Catherick and Anne are one of the few parent-child pairings presented in the novel, and this would seem to suggest that Mrs. Catherick would care most strongly about protecting her daughter. Yet, she is completely cold and does not seem even to care that Anne is dead. Especially given how much Victorians emphasized the bond between mother and child, this scene would have been horrifying and chilling. For Mrs. Catherick, Anne has always been simply a reminder of her mistake and an unwanted burden. She is traumatized by the ostracism she faced when the scandal took place, and she devoted all of her energy to restoring her reputation and being considered respectable again. She was eventually successful at this, but it left her with no energy to love her own child.