Ooh - not Massachusetts: Middletown, Connecticut. A young boy jots down musical scores as his dad drives their car through a rainstorm. The boy asks his dad to slow the windshield wipers because their tempo is messing him up. A shout is heard: "I need help!" A lady flags them down, saying her car won't start. The father calls a tow company and then takes a look under her hood. (Not a euphemism.) Strange red and green lights on the engine start flashing and the man is mesmerized. He snaps out of it when the tow truck arrives, but the lady and her car are gone. So is Ben, the man's son.
Broyles brings Olivia and Peter up to speed on the abduction. This isn't the first time it's happened: at least three other incidents with the same MO are in their files. The missing persons, all academics, were recovered but all were severely disturbed afterwards. One guy even tried to lobotomize himself with a butter knife. Walter asks if there were red and green flashing lights - yes - but when pressed for more information can't recall anything else germane.
Olivia visits the dad in Connecticut to hear his story. She tells him that she believes him but she can't understand why the woman picked Ben since he wasn't an academic expert like the others. The dad explains that Ben was recently in a car accident (that killed his mother) and when Ben awoke from his coma, he'd become a musical prodigy. Hm, goes Olivia.
Ben is chained in an awful cell. He taps his foot in counterpoint to the swirl of the ceiling fan. The kidnapper comes in to see him and tells the little boy that his mother is awfully excited to see him. Ben is confused - isn't she dead?
At the Harvard lab, Walter is trying to remember more about the flashing red and green lights and, in the meantime, recalls some tests he did in which a trance was induced via flashing colored lights. He thinks that the lights put the dad in a hypnogogic state during which Ben was abducted: the key to the trance is the specific wavelength of the colors. Walter starts a series of green and red lights flashing while Peter watches, bemused. A short time later, he looks up when Astrid comes in with lunch. He tells his dad that it obviously didn't work. Astrid: "What's up, Chachi?" Peter looks down to see that he's cut the sleeves off the sweater he's wearing. "Did you do this to me?" he asks, waving a pair of scissors at his dad. No, replies Walter, you did it.
Charlie calls Olivia, letting her know that they've identified the kidnapper: Joanne Osteler, a scientist from MIT ... who died ten years ago. Either she faked her death or Olivia is chasing a ghost. By the time Olivia gets to the lab, Walter has remembered who told him about the red and green flashing lights: one Dashiell Kim, who disappeared a few years ago, returned, suffered a psychotic break and bludgeoned his wife to death with a tire iron, and got committed to the same lunatic asylum that Walter had been in.
Olivia tells Broyles that she needs to get into the asylum to talk to Kim. He says that'll be tougher than she thinks: Kim is classified as criminally insane with knowledge of state secrets. She'll need extra official clearance to get in to see him, and that could take months for the paperwork to clear. Gosh, if only they had a connection to the asylum ...
Joanne the dead MIT scientist walks little Ben through some horror movie-esque tunnels, bringing him to a room containing a piano and all his handwritten music pinned up on the walls. "You've never looked at it in that order, have you?" she asks. No, says Ben absently, enrapt. Then he turns: his mom is standing there. She calls him "Bean" and gives him a big hug. Creepy Joanne watches impassively.
Olivia reports to the Bishop boys about Dashiell Kim's status. She's got a crime scene photo of Kim's wife: formulae are written all over the walls behind her body. Ben's piano music is playing in the background ... blah blah blah ... Walter and Peter realize that Ben's unfinished piece is the musical equivalent of Kim's incomplete formula. The question is: what were they trying to solve?
Ben asks his dead mom how it is that she's here with him. She says she doesn't know, but what's important is that he finishes his song. He says he'll try and gives his dead mom a big hug.
Olivia asks the asylum's administrator if she can see Kim. The administrator goes off topic to say that Walter, a former resident, is in no shape to be out and about, much less helping the FBI with weird science. And then he tells her that she can't interview Kim: too traumatic for the man. Olivia's like, did I mention a little boy's life is at stake? The administrator proposes this fabulous idea: Walter, a familiar face, can meet with Kim.
Peter is outraged when Olivia presents their options. How can she think of taking his borderline mental dad back to the asylum to run an interview, especially when it's likely that Walter won't remember anything Kim says since Walter scarcely remembers lunch on any given day. Walter calmly objects to his son's speaking about him as if he weren't standing RIGHT NEXT TO HIM. Peter asks his dad what he wants to do. Walter says he'd rather not go back to the asylum but he will. He wants to help little Ben. Peter is on record as this being a Bad Idea.
Yikes. There are armed guards all over this part of the asylum. Walter looks nervous as the administrator takes him to see Kim. This is an awful place.
Walter sits down next to Kim and they shoot the shit for a bit about institutional meds. Then Walter gets right to the point: where did that woman take Kim when she abducted him with the red and green flashing lights. Kim clams up immediately so Walter borrows a crayon from another inmate and starts writing Kim's formula on the table. Kim protests that he doesn't do math anymore - it's not conducive to his mental stability. Walter presses. "I don't do math anymore!" shrieks Kim, sending all the other inmates into an uproar. Walter gets agitated himself, grabbing Kim and shouting about the flashing lights. The orderlies grab Walter and inject him with a sedative.
Peter is furious: what do you mean you sedated my father when I am his guardian?!! The administrator reiterates that he thinks the worst features of Walter's mental illnesses are being exacerbated by his field work with the FBI. Olivia tells him that he's obstructing a federal investigation but the administrator is all, bring on the court order, lady. Walter has to stay overnight in the asylum: he whimpers in his bed, especially when he sees himself walk through the door, sit down on the bed next to him and welcome him back.
Back at FBI HQ, Olivia gets confirmation that they'll have their court order tomorrow morning to release Walter. She apologizes to Peter for putting his father at risk. Since he doesn't have to babysit tonight, Peter decides to help with the kidnapping investigation: looking for probable aliases for Joanne. Her real last name is "Osteler," and that is Middle English for "innkeeper," so he starts to search for Joannes with hotel last names: Marriott, Hyatt ... he finds a "Joanne Ritz" with a P.O. box in Clarksburg. (Clarksburg came up earlier in the episode but I don't remember the connection and don't care enough to go back. Sorry.) They expand the search to Clarksburg.
Ben and his mom sit at the piano. Ben is working on his song but he's struggling. Creepy Joanne Osteler lurks, staring. "I don't know how it ends!" Ben says, frustrated. Immediately his mom's face starts dripping blood. A gaping wound creases her face. Ben cries for Joanne to stop whatever she's doing. Joanne: "It's up to you, Ben. If you lose your mom again, you only have yourself to blame."
The next morning, Walter tries again with Dashiell Kim, first apologizing for upsetting him. Kim tells him to go away. Walter persists: where did the woman take you? Kim pleads, saying he can't, but Walter insists. Finally Kim says it was beautiful. Joanne brought him everything he wanted - cut to Ben hugging his mom. "Then she took it all away when I couldn't solve the equation." Cut to Ben's mom bleeding on the piano keys. Kim says that Joanne tortured him - cut to a zoned-out, twitchy Ben strapped down with electrodes on his head, playing a keyboard while Joanne takes notes - while she sucked the information she wanted out of his head. "But I couldn't give her what she wanted!" Walter grabs the other man, telling him to focus on where he was held. But all Kim can remember is a red castle, like in a dream.
The administrator still doesn't want to release Walter, saying Peter isn't a fit guardian what with his checkered past. He's going to petition the court to send Walter back to the asylum. Peter's like, do NOT fuck with me and my dad, man. The administrator finally lets him see Walter. Walter would like to go home now since he failed at his assignment. Kim was a loon, he says, going on about dungeons and red castles. "Is that what it's like, talking to me?" he asks his son. Peter is sad.
Peter calls Olivia to report a bust on their end. She promises to let them know if she comes across any red castles. And after she hangs up, she looks across the street at a red brick building with a turret on top. Well, that was easy.
They open the castle door: it's an old carousel. Because the episode is almost over, Olivia quickly finds a trap door and she and Charlie head into the tunnels below, guns and flashlights drawn. It doesn't take too long for her to find Ben in Joanne's secret lair. As she tries to untie him, Joanne jumps her. Chick fight! It's a pretty violent one too. Joanne gets away and Olivia chases her for a bit until Joanne manages to push the button on her remote that starts the red and green lights flashing in the tunnel. Olivia trances out until Charlie finds her again. Joanne has gotten away.
Peter and Walter return to their hotel room. Walter is kind of twitchy and tells his son that he thinks he's ready for his own room. Peter promises to talk to Olivia about getting into some campus housing. Then he tells his dad that he's proud of him for volunteering to go back to the asylum. Walter stops fidgeting for a moment and says thank you.
Joanne pulls up somewhere and tells some guy, "Got it. Let's see if it really does what you say it does." The guy puts an apple inside a safe and then attaches some plungers and other gizmos to the outside of the safe. They key the formula into a computer. There's some whumping noises and the guy reaches his hand through the back wall of the safe and pulls out the apple, intact. Joanne rejoices: "It worked! That's incredible!" The guy shoots her dead and takes a bite out of his apple.
Ben and his dad are reunited at FBI HQ while Olivia and Broyles look on. Olivia is sporting a nice shiner. She says that she needs to call Walter to let him know that Ben is okay. Broyles nods, smiling just slightly, and tells her that she did a good job.
2 hours ago