The third episode of The Woman In The Wall opens with the Kilkinure community mourning the loss of Clemence, Lorna’s closest friend from the laundry.
Before Lorna could see her and inquire further about the whereabouts of their children, David discovered her dead at the conclusion of The Woman In The Wall’s second episode. The latest episode then shows Lorna’s mental condition continue to deteriorate as the toll her lack of sleep is having on her. In the meanwhile, Detective Colman Akande pursues Lorna as a leading suspect in the case of Aoife Cassidy’s disappearance, but he encounters resistance from Sergeant Aidan Massey.
The third episode begins with Lorna kneeling over Clemence’s remains in her coffin and recalling a moment when they had been lying next to one another and had been discussing their dreams for their unborn children.
While all of this is happening, Colman awakens from a nightmare. After seeing the CCTV footage from the shop again, he realises that the woman is Lorna Brady. Colman is resolved to confront Lorna at Clemence’s burial, despite Massey’s advice to the contrary. On the day of Clemence’s burial, he says, they won’t talk to Lorna.
Because she is having trouble adjusting, Lorna has begun to hear and see things that aren’t there, including images of Aoife Cassidy. Lorna goes over to David, Clemence’s brother, during the wake to inquire whether she has told him anything about what Aoife has told her.
Lorna is rejected by David while he is mourning. Then Colman crosses her path and asks Lorna to return to the station in the morning. Michael defends her, and Massey is compelled to intervene and apologise on Colman’s behalf for his lack of subtlety.
Later, Lorna and Amy start arguing, and David steps in by asking Lorna to accompany him home. When Colman discovers Amy sobbing by herself, she explains to him that she witnessed Lorna lighting Father Percy’s car on fire and that she had only before lied to protect her.
David shows Lorna a picture of a young child at his residence, and Lorna immediately recognises the child as Clemence. David clarifies that the girl is in fact Breda, the daughter of Clemence, and that his sister had met a Sister of the Seven Joys who handed her that same photo. Lorna interprets the vision as suggesting that someone else could be aware of what happened to her daughter, and David thinks that his sister would have wanted Lorna to see it.
The next morning, Lorna shows up for interrogation. Michael had previously advised her that soldiers apply hot sauce in their eyes to prevent sleep, so Lorna does the same.
However, Lorna rejects Colman’s push and attempts to link her to the disappearance of Aoife Cassidy. When Lorna’s eyes begin to haemorrhage, Massey ends the interview and attempts to get Colman to calm down once again. While everything is going on, Lorna exits the station and walks down the street after a vision of a lady she believes to be Aoife Cassidy, almost being hit by a car in the process. Fortunately, Michael is moving by and intervenes to save her.
After giving Michael the image of Breda, Lorna tells him she believes it may be evidence that her own kid also survived. After she complains about her visions, he counsels her to get some rest. She then asks if he will watch her sleep since she does “bad stuff” when she drifts off on her own.
Michael reluctantly consents. Later on, though, he awakens to see Lorna standing in the kitchen. As he approaches, she snatches up the photo with a pair of scissors and strikes out at him, but he manages to wake her up by sprinkling her with water. After that, Michael goes to the hospital to have the wound she gave him examined.
Aoife Cassidy sighting reports are being investigated by Colman and Massey, despite Colman’s opinion that their efforts are a “waste of time.” Instead, he visits Dara in jail and persuades him to assist him in looking for his missing wife.
Dara affirms that the lady holding the axe in the CCTV tape is Lorna, and he advises Colman to research into “The House of The Sacred Shepherd” since he claims Aoife was wary of them.
When Olivia notices the hogweed burns on Lorna’s wrists, she wonders whether Aoife may have buried any proof of what had happened to the convent children. As a result, Olivia brings Olivia back to the home of the distraught lady to look into this possibility.
The disappearance of Aoife, Lorna, and Father Percy are all connected, according to Colman, who learns that the House of the Sacred Shepherd was an adoption agency that collaborated with Kilkinure convent. Sadly, the House stopped functioning in 1979, and Lorna didn’t give birth until the 1980s. He doesn’t see why Dara would have brought it up, but the other Garda members don’t appear to agree.
Under a weak floorboard in the ancient building, Lorna discovers a hidden cache of envelopes, but she keeps her discovery a secret from Olivia. The young lady refuses to answer a phone call, revealing herself as an unidentified individual.
Olivia just states that the message is from her father, who has remained in Dublin, when Lorna informs her she may respond if she needs to. However, if Olivia truly was Dara’s daughter, she would be aware that her father is incarcerated. Later, Olivia requests to remain with Lorna because she doesn’t know anybody else in the area. Lorna accepts and instructs Olivia to look downstairs. However, when Olivia is preoccupied, Lorna sneaks away to her car and flees with the bag.
A little farther down the road, she stops and searches through the stack until she finds an envelope with her name on it. When she opens it, she discovers Agnes Brady’s death certificate, which states that she shivered to death after only a few days.
Devastated, Lorna arrives at her house to see Colman looking about. When she only gives him a cup of tea and inquires as to whether he found what he was searching for, he is taken aback.
Colman explains his theories: Aoife Cassidy killed Father Percy in Dublin, then she and Dara travelled to Kilkinure, and he believes Lorna assisted Aoife in smuggling herself into the community for some unknown reason.
He deems her a blatant liar when she claims she isn’t aiding Aoife. She displays the death certificate, which is signed by Aoife Cassidy when he brings up the disappearance of her child and bemoans the fact that she was unable to be there to protect her own daughter from harm.
When Lorna hears a pounding noise, her paranoia intensifies. Colman, who is understandably concerned, asks asking what’s wrong, but Lorna soon loses it and yells out a confession: she killed Lorna and hid her in the walls of her house.
In a shocking finale, Lorna destroys the wall where she concealed Aoife’s body but discovers nothing there.