The Other Mrs.

Details of Sadie’s mental-health condition are discussed in this section, as well as her awareness of it. As a teen, she was diagnosed with bipolar disorder and placed on a series of medications, none of which seemed to help.

Sadie betrays Imogen by telling Will about the teenager’s role in Alice’s suicide, but Will does not believe her.

Sadie finds objects that connect to Morgan’s murder and lead her to conclude that the killer is living in her house. One is a silver necklace with the letter M and the other is a bloody washcloth, the latter of which she hides until she can talk to Will about it privately and then give it to the police. She is feeling physically ill and also loses more time.

Mouse’s narrative is picked up right after her sneeze. She is frozen at the top of the stairs, waiting for Fake Mom to appear. When she doesn’t, Mouse returns to her room and talks to her deceased mother, whom she imagines answering her.

Sadie is left alone in the house after everyone leaves for work or school. Her mind is racing, and new thoughts are triggered by small events. She finds another violent drawing in the hallway and wonders if Otto is regressing. She thinks of her therapist and her childhood, then calls Will, who should be on the ferry to work. She tells him about the bloody washcloth and reiterates her theory about Imogen’s involvement in the murder. When he tells her to stop blaming Imogen for everything, she then moves on to Otto’s possible guilt.

Otto returns home saying he is feeling ill, and Sadie is so afraid of her son that she looks for a weapon to use against him. He confronts her for betraying him in the past because it had been her idea for him to use the knife against his bullies. The Sadie who plotted revenge with him was wearing black and smoking, so she finds his story ludicrous. She does, however, understand that he believes the story he is telling her. While checking on ferry delays online, she discovers the search history on Erin Sabine, Will’s dead fiancée, including a family photo. Erin is pictured with her parents and sister; Sabine thinks something is familiar about the photo but she can’t put her finger on what. She is distracted by the dogs barking in the yard and is horrified to discover they have dug up the missing boning knife. She heads off to the police station in her pajamas.

Fake Mom comes up the stairs in the middle of the night and puts Mouse in the dog crate for not having flushed the toilet and peeing on the toilet seat. She also kills her guinea pig, Bert, with a dull knife in front of her.