"Motherboard" is the fourth episode of Season 2 of Mr. Mercedes. It aired on September 12, 2018.
Hodges is rattled by the unexpected death of a hospital staff member. Jerome offers much needed help in Hodges's quest to uncover the truth. Brady works to master the limitations of his newfound ability. Already struggling to cope, Lou suffers additional setbacks.
The police secure the scene where Sadie apparently killed herself, and take Bill's and Maggie's statements. Felix arrives at the hospital and come over, and Maggie approaches him and he asks what happened. Maggie explains that Sadie just jumped and had been acting off earlier. She explains that earlier Sadie had apparently given a patient a morphine overdose, and explains about how the nurse had put in a transfer.
After Bill finishes giving his statement, Montez comes over and introduces himself. He asks what brought Bill out, and Bill says that Maggie is a friend of his. Montez points out that Sadie treated Brady, and says that he heard that Bill used to go into Brady's room. Bill says that he wanted to be there when Brady woke up, and he stopped when he realized Brady wasn't going to wake up and walks off.
Later at home, Bill, reads Internet articles about coma patients communicating with their doctors. Holly comes in and asks Bill how he's doing, and sees what he's reading. She wonders if he thinks Brady is conscious, and Bill tells her that she needs to his respect his solitude. Holly says that his sentiments hurt her feeling, and abruptly leaves.
In his mind-basement, Brady meditates and listens to music. In the real world, Maggie tends to Brady as Felix examines Brady's EKG and determines that it spiked but hasn't changed. Maggie says that it happened twice, the second time around when Sadie died. Brady watches them on his monitors as Maggie tells Felix that Sadie was epileptic but had it under control. Once the attending physician, Dr. Seth, leaves, Felix closes the door and tells Maggie that they should schedule Brady for the fMRI equipment to determine if Brady is conscious and take a spinal tap as well to check for infection. He then asks Maggie about Bill, and warns her to maintain doctor-patient confidentiality or her job is at risk.
Brady turns to his mother's gravestone and says that he'll have to find another epileptic.
Mrs. McDonald comes to the office and asks Bill why he was trespassing on her property the night before Sadie died. Bill says that he was investigating Sadie because some of her coworkers were worried Sadie was a danger to herself and others. He refuses to say who the coworkers were, and asks if Mrs. McDonald noticed her daughter acting erratically. The woman says that she didn't and asks if Sadie was involved with something. Bill says he was trying to determine that, and Mrs. McDonald tells him to stop investigating because the police have written it off as a suicide. He figures that Mrs. McDonald doesn't believe it was a suicide, and she says that it doesn't matter what she thinks. Bill disagrees, and Mrs. McDonald insists that Sadie was happy. He tells Mrs. McDonald that Sadie got a bit violent with him and almost overdosed a patient, and that something seems amiss. Mrs. McDonald says that she last saw Sadie three days ago and her daughter seemed fine.
Maggie and an orderly take Brady to the fMRI and then bring him back to his room. Brady is unable to access Maggie's mind, and Robi appears in Brady's mind-basement and tells him to work the problem like he taught him to and focus on the process.
Bill and Jerome work on Ida's gazebo and Jerome points out that Bill isn't saying much. Jerome brings up Sadie's death and Bill refuses to talk about it. Jerome suggests that Bill look into Sadie's diary, and suggests that Bill get into Sadie's phone.
Lou wakes up when she hears Steph in the kitchen, hides her alcohol bottles, and goes out to her girlfriend. Steph's luggage is packed, and Steph says that she can't watch Lou hurt herself anymore. Lou tells her that she can't leave right now, and promises to do better and she loves her. Steph explains that she care for Lou but doesn't care about her, and she doesn't know what she can do Lou anymore. Lou begs her to stay and tries to kiss her, but Steph apologizes and leaves for her mother's house.
Bill prints out an article on a comatose woman convincing a man to kill himself. Montez arrives and Bill invites him in. They drink beer and Montez tells Bill that Mrs. McDonald said Bill was snooping around her house. Bill says that Sadie tried to attack him with a scalpel and almost overdosed a patient, and her colleagues said that she was acting unusual. Montez wonders if it's tied to Brady, and points out that Bill held stuff back to the point that it endangered people's lives. He wants to have a frank conversation with Bill about what he knows, and Bill agrees.
At the hospital, Al sets up a small shrine for Sadie. He then goes into Brady's room, turns off the lights, and makes sure that Maggie isn't watching. Al then closes the door and turns on the TV to a program about elephants. Brady isn't amused, and Al sits down and plays with Brady's donated Fishin' Hole game. Brady notices as Al slips into a semi-trance playing the game and slips into Al's mind.
Bill tells Montez that he didn't report the scalpel incident until he could confirm it. He figures that he was in right in retrospect, and doesn't know why Sadie went rogue. Montez points out that his father on the force said that Bill could always figure thing out, and goes to the bathroom. Bill takes the beer cans out to the kitchen and then comes back to find Montez in his office looking at his board of articles. Montez says that Bill is obsessed with Brady, and Bill finally tells him that Brady is more aware than he lets on. He yells at Montez to check the doctors, and suggests that Brady found a way to communicate with Sadie and is faking the coma. Montez dismisses Bill's suspicions, pointing out that people can't fake comas, but Bill isn't convinced. Disgusted, Montez leaves.
Brady tries to control Al, but a nurse outside drops a tray, bringing Al out of his semi-trance. Al turns off the TV and goes on his rounds delivering books. He takes the game with him and starts playing it, and Brady connects with Al again. "Robi" tells Brady that he hypnotizes people. Robi's head wound starts bleeding and he asks for Hot Pockets, and Brady tells him to check the freezer.
Lou goes to a bar and drinks, and the bartender reluctantly pours her another. A girl, Pixie, sits next to Lou. Lou says hi to her and buys her a drink, and Pixie accepts.
All goes off into a trance and Brady has him walk out of the hospital.
A drunken Lou and Pixie leave the bar together and they kiss. Lou invites Pixie to her apartment, and Pixie leads Lou off.
Brady controls Al and takes him to his car.
A ratty guy follows Lou and Pixie, and asks to watch. Lou yells at him to back off, and sprays him with pepper spray when he comes over. She kicks him, ignoring Pixie, and Pixie runs off. Lou kneels and punches the man repeatedly, and police officers arrive, draw their guns, and order Lou to stop.
The next morning, Brady has Al drive to the community center where Brady killed the job attendees. There's a memorial plaque to the people murdered, and Brady is disappointed that's all that there is. The entranced Al picks up a teddy bear and tears the head off, then drops the pieces on the ground and goes back to his car.
Bill approaches Mrs. McDonald as she returns home and she says that she complained to the police about him. He asks to see Sadie's phone because he wants to see if there's anything in Sadie's text that could explain what happened. Bill warns the woman that the police don't care and he's the only one who can pursue the matter. He figures that Mrs. McDonald won't believe why he's interested, and she agrees to let him take the phone but warns that she doesn't have the password.
The police release Lou when Steph posts bail. Steph is waiting outside and Lou says that she's sorry. Lou tries to explain what happened, but Steph doesn't want to hear it, says that she can't anymore, and says that Lou put the man in the hospital. Steph tells Lou to take a taxi home and they're done, and walks off.
Holly approaches Ida as she works on the gazebo and offers to help. However, she admits that she isn't very good at construction. Ida asks how weird Holly is, and Holly says that she's very weird. Ida gets her a beer and asks what's up, and Holly says that Bill is hiding things from her and he never used to do that. She worries that Bill is going to risk everything they worked for something that doesn't exist. Ida has no idea what she's talking about, and Holly says that the "case" just gives Bill a chance to pursue his obsession with Brady. The older woman tells Holly that she doesn't need anyone to survive, and that they should give Bill the benefit of the doubt. Holly explains that Bill thinks Brady is faking his coma, and Ida points out that Bill has always been right before... including about Holly. She says that she doesn't want Holly to depend on Bill, but says that she can count on him. Holly admits that it doesn't make sense, and Ida tells her to help her with the gazebo because that's all she's got.
Jerome hacks Sadie's phone for Bill and admits that what he's doing is "extracurricular". Bill gets a beer and goes outside to wait, and sees Ida and Holly together at the gazebo. He goes back inside and Jerome accesses the phone's memory chip, and they find texts from Sadie to Matthew saying that "he" is inside her head. Bill figures that the texts prove his suspicions, and he goes back to his office. Outside, Al parks out on the street.
- Brendan Gleeson as Bill Hodges
- Harry Treadaway as Brady Hartsfield
- Kelly Lynch as Deborah Hartsfield
- Jharrel Jerome as Jerome Robinson
- Scott Lawrence as Peter Dixon
- Robert Stanton as Anthony Frobisher
- Breeda Wool as Lou Linklatter
- Justine Lupe as Holly Gibney
- Mary-Louise Parker as Janey Patterson
- Holland Taylor as Ida Silver