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"The Collaboration Contamination" is the fifth episode of the eleventh season of the American sitcom The Big Bang Theory. The episode aired on Monday, October 23, 2017.


Leonard and Penny use a parenting book of Bernadette's to control Sheldon's behavior. Howard and Amy start working long hours in her lab, causing Raj, Bernadette, and Sheldon to get jealous and lonely.

Extended Plot[]

During a group dinner with the gang, Bernadette thanks them for letting her put Halley in Leonard and Penny's room, even though she did throw up on Leonard's Ewok. Amy doesn't want any Ewoks in her bedroom and drew the line at Sheldon's Chewbacca. Amy is working on a way for controlling robotic limbs with brain waves. Howard makes a helpful suggestion and then agrees to work with Amy. He is the world's best engineer or so his coffee mug says.

Leonard comes down the hall and finds Penny reading a parenting book. No, she is not pregnant. Sheldon comes in and wants a ride since Amy is working odd hours with Howard. Leonard said that it's fine since he has been driving him for years. Unfortunately Sheldon has a new car game where he imitates sirens.

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Penny managing Sheldon.

Howard is drooling over all of Amy's fancy new lab equipment and her coffee maker. He inspects her cap device that is used to map the brainwave output so she can control anything. Howard quips that from that ring on her finger, she has gotten good controlling robots. Amy warns him that that is her finance and she can control him to hurt Howard.

Leonard is getting a headache as Sheldon keeps imitating various sirens. Leonard finds it interesting that Amy is working together with Howard. Sheldon is neutral on the subject. Normally he tunes Amy out when she complains about her co-workers, but he joins right in complaining about Howard. He denies that he is complaining of Howard. He denies that is jealous about runs a train. Then Sheldon starts to imitate train whistles to Leonard's disdain.

Amy and Howard are working together when Sheldon shows up to check up on them. Amy was happy to see him. Sheldon starts blinking so that they can talk about Howard in front of him. Amy doesn't know Morse code and doesn't want to participate. Howard stands up and says that if you want to say something, say it in front of him, but Howard's Morse code is too rusty too understand Sheldon.

That night in apartment 4A, Sheldon is complaining that Amy says that she will return at eightish which is too inaccurate for Sheldon. Penny invites Sheldon for dinner, but he declines. With Amy not home, Sheldon is frustrated. Penny says that it is okay to be frustrated using her new parenting skills. Sheldon agrees as Penny says that his feelings are valid. Penny continues. "Now go wash up and we'll call you when dinner is ready." Sheldon leaves happy. Leonard is amazed and asks if she was a witch. Penny explains that Bernadette's book works, but only up to age five. When Sheldon turns six, he plans on leaving him at the zoo.

Raj visits Bernadette and complains that Howard had been at work every night this week with is work wife. Bernie thought that Raj was his work wife. Raj wanted to know if there was anything he could do for her. Howard has been missing some of his chores since he was away. Raj reiterated that he meant emotionally. Howard is excited about is work and Bernie is proud of him, though is still pregnant and has a lot of work to do.

Amy gets home and Sheldon asks about her day until she mentions Howard. He plans to pamper her and gets Amy her 1notebook they had on the project THEY had been working on together. Sheldon wants them to work on it, while Amy is tired. Finally he bugs her enough that she agrees to work on it the morning. Sheldon gets mad and starts sounding like he is arguing about sex instead of science. Penny goes to check the parenting book. The advice is to give him options that are acceptable to oneself. Leonard gives Sheldon the options of driving him in two hours or taking an Uber. Sheldon chooses the Uber to both of their surprises.


Sheldon romancing Amy.

Visiting Bernadette, Sheldon complains about them working together on a weekend. His presence is bothering Bernadette. Sheldon wants Howard to feel as angry as he is, so Bernie suggests that he make Howard jealous by doing something he loves to do. She tells him how much Howard loves to do chores. Before that she asks if he ever read "Tom Sawyer". First she gets him to change the batteries in the smoke detectors.

While working on the software, Howard tells Amy to check the brain model. Inside was the playing card she had chosen earlier. Amy is ecstatic. While waiting for the software to compile, Howard suggests that they put on some Neil Sedaka songs. They start to sing and dance to "Calendar Girl". Raj catches them when they said that they were working. He wants Howard to go to the movies with him.

Back at Bernadette's, Sheldon has changed the batteries in the smoke detector and has done the laundry. Sheldon thinks that Howard will be steamed like his shirts were. Next she has him clean the oven while she sits with her feet up eating ice cream out of the tub. Raj then shows up with his news about Howard and Amy having fun. Sheldon breaks in that Howard won't have any fun after he finds out Sheldon did all his favorite chores. Raj bursts that 1myth. Sheldon realizes that Bernie played on his own gullibility and would storm out, but he hasn't finished cleaning the oven yet.


Baby 2 on the way!

Now Sheldon is complaining to Leonard and Penny about Bernadette; Leonard explains that Amy and Howard working together is not a big deal. Sheldon is worried because Howard has Amy laughing and listening to music. Penny says that she is proud that he is expressing his feelings which calms Sheldon. Penny adds that everyone gets mad, even mommies and daddies. Leonard doesn't like the way Penny was handling Sheldon and then she starts learning her new parenting knowledge on Leonard. Leonard sounded frustrated, but Penny was proud of the way he was stating his opinion. He tells Penny not to use the book on him as Sheldon picks up on what's going on. He shouts that he won't be treated a as child and then storms out of the apartment.

Later Penny asks Leonard if that is the way he was going to handle their children by throwing her under the bus. He thought that she was just spoiling Sheldon. She claims that some things she is just smarter at. And no sex tonight.

Amy gets a text from Sheldon that he is upset with Leonard, Penny, Bernadette and Mark Twain. Bernadette told Howard that Raj was getting on her nerves. Amy thinks it is late and then tries to look at her watch which is now on her mounted skeleton. She is shocked and shouts "How is that even possible!" as Howard looks smug.

Raj is now hanging out with Sheldon planning to watch TV. Sheldon agrees and then tells Raj who the killer is.



  • Title Reference: Sheldon gets jealous of Amy and Howard working together. Bernadette and Raj also get angry over the situation.
  • Taping date: September 19, 2017
  • This episode was watched by 13.20 million people with a rating of 2.8 (adults 18–49).
  • Total viewers including DVR users 17.96 million.
  • The Big Bang Theory was ranked #4 for the week ending 26 October 2017.
  • This episode aired in Canada on October 23, 2017.
  • Chuck Lorre's vanity card. [1]


  • Caroline Preece at Den of Geek! - When all else fails on The Big Bang Theory, the writers seem to fall back on a shakeup of dynamics. They did the arc where Sheldon and Raj teamed up at work, and the awkward hilarity of the scavenger hunt pairings a couple of years back, and now it appears we'll be allowed to enjoy a new friendship between Howard and Amy...Simon Helberg has long been one of my favourite actors of the core group, and watching him and Mayim Bialik goof around with close-up magic and dancing to Neil Sedaka is an absolute treat. Past experience indicates that the fun will be short-lived before we return to the status quo, but I'll enjoy it while it lasts...Though this episode felt a little undercooked overall, it did manage to weave everyone in and out of each other's storylines better than it usually does. [2]


  • Leonard asks Penny if she is a witch after she gets Sheldon to do what she wants. On "Charmed", Kaley Cuoco did play a witch name Billy an friend of the Charmed ones until the last season.
  • Penny again treats Sheldon as a child.


Bernadette: Thanks for letting me put Halley in your room.
Leonard: Yeah, no problem.
Bernadette: Oh, and Penny, she kinda threw up on your stuffed bear.
Penny: Oh, that's okay.
Leonard: Hey. Tha... that's an Ewok, and it's mine.
Penny: Yeah, which is why it's okay.
Sheldon: See? He gets Ewoks in his bed.
Amy: You've got Chewbacca. That's enough.
Raj: I used to have the stuffed racoon from "Guardians of the Galaxy", but Cinammon licked it raw.
Howard: There's a time and place for your randy dog stories, and... it's never and nowhere.

Penny: No more stories about sex, so, Amy, that brings us to you.
Amy: Well, at work, we've been doing some interesting work with neuroprosthetics.
Penny: Neat. I've been re-watching "The O.C.", so we're all leading productive lives.
Amy: We've been working on a computer interface that can use brainwave patterns to control robotic limbs, but we're having a little trouble localizing the signal from the EEG cap.
Howard: Oh, well, have you thought about adding a phased array of sensors for better localization?
Amy: Actually, that never occurred to me.
Penny: It never occurred to me I would miss the Ewok conversation.
Leonard: Good, 'cause I just bought another one on Amazon.

Amy: You know, I could use an engineer on this project.
Sheldon: Well, now this works out great. Howard's an engineer. I'm sure he knows someone qualified.
Howard: She was talking about me, Sheldon. I'm perfectly qualified.
Bernadette: Yeah, Howie's the world's best engineer. It says so right on his coffee mug.
Penny: Aw, you got him a mug?
Raj: I did. But it's not a competition.
Bernadette: Yeah, I lost that battle years ago.
Amy: So, Howard, are you interested?
Howard: Are you kidding? If I could control robot arms with my brain, I'd be able to do so many things.
Sheldon: Really? Because you've been controlling human arms with your brain for years and not much has come of it.

Leonard: Hey. What you reading?
Penny: A parenting book.
Leonard: Oh, my god. Are... are we...?
Penny: What? No! You think this is how I would tell you?
Leonard: Well... [he stammers]'re sitting there with a book. It felt like anything was possible.

Penny: [reading a book on parenting] Bernadette left it here.
Leonard: Yeah? Anything interesting?
Penny: Well, I just saw a picture of a baby's head crowning, so I hope you enjoyed sex, because we're done with that.

Sheldon: Remember how disappointed you were when Amy started driving me to work?
Leonard: [sarcastic] Sure. Sometimes people smile a big smile of disappointment.
Sheldon: Yeah, well, good news. Amy had to go in early to show Howard around her lab, so you get to drive me.
Penny: [Leonard's face falls] Aw, his smile of disappointment has turned into a frown of joy.
Leonard: It's fine. I've been driving him for years. What's one more day?
Sheldon: Oh, and I've got a new car game we can play. It's called "What Siren Am I?".
Leonard: Kill me.
Howard: So this is it?
Amy: Yes. We are using it to map brainwave patterns and then converting them into electrical impulses that can be used to control anything, from wheelchairs to robots.
Howard: Based on that ring on your finger, I'd say you're pretty good at controlling robots.
Amy: Careful. That's my fiance you're talking about. And I can program him to hurt you.

Leonard: [wearily playing Sheldon's car game] I don't know. French police?
Sheldon: Oh, so close. Belgian ambulance. All, right you ready for your next one? Just a warning, this one's a little annoying.
Leonard: Let's take a little... little break. I'm getting a headache.
Sheldon: Aw. Right in the middle of our fun game.
Leonard: Yeah, weird.

Leonard: So... Howard and Amy working together. That's interesting, huh?
Sheldon: Eh. It's all right, I suppose. Usually when Amy complains about her coworkers, I just tune her out, but now I'll be able to join in and pound away.

Howard: If we add phase detection to your EEG sensors, I'll have to re-write most of the code.
Amy: Well, can you do that?
Howard: Well, these hands were made to do three things: close-up magic, writing code, and the dirty shadow puppet show that got me kicked out of Hebrew school.

Amy: What's with the blinking?
Sheldon: It's Morse code. So that we can talk about... [he gestures at Wolowitz]
Sheldon: ...without hurting... [he gestures at Wolowitz again]
Sheldon: ...'s feelings.
Amy: Sheldon, I don't know Morse code.
Howard: I do. And if you have something to say, you can say it to my face.
Sheldon: Oh. All right. [he blinks in Morse code]
Howard: I'm a little rusty. Could you say that again?

Penny: Okay, what is going on?
Sheldon: Well, ever since Amy started working with Howard, she hasn't been home.
Penny: Didn't that just start this morning?
Sheldon: And has she been home?
Penny: You know, that would frustrate me. Does it frustrate you?
Sheldon:I-it does.
Penny: I get that. You know, it's okay to feel frustrated when things aren't going your way.
Sheldon: I suppose. Ah, maybe it's not that big a deal.
Penny: No. No, no. Your feelings are valid. Now, why don't you go wash up and we'll call you when dinner's ready.
Sheldon: Okay.
Leonard: [Sheldon leaves] What did you do... are you a witch?
Penny: No, I've been reading Bernadette's parenting book. It's like the answer key to the Sheldon test.
Leonard: That's amazing.
Penny: I know. But, you know, it's only birth to five. What do we do when he turns six?
Leonard: Take him to the zoo and leave him there.

Bernadette: Howard's not here.
Raj: Oh, I know. He's been at the lab every night this week with his work wife.
Bernadette: That's weird. I thought his work wife was standing in my kitchen.
Raj: Don't be snippy. I came to see how you were doing. Like, uh, do you need help with anything?
Bernadette: Oh, thank you. There are a few things around the house that I've been waiting for Howard to get to. The smoke alarms...
Raj: No, I meant emotionally. How are you feeling?
Bernadette: Like you're not really here to help me.
Raj: Wow. Still snippy.

Bernadette: Everything's fine. Howard's really excited about his work, he's been in a great mood. I'm really proud of him.
Raj: And I can fit into the pants I wore in high school. Come on, we don't need to lie to each other.
Bernadette: You're right. I have a teething baby, I'm pregnant, I have a proposal due tomorrow. I don't have time to hear about how much you're missing my husband.
Raj: Well, I think I know why he's been working so late.

Leonard: Sheldon's texting me to drive him to Bernadette's.
Penny: Well, what are you gonna say?
Leonard: Well, they did just introduce the middle finger emoji. If it's not for this, I don't know what it's for.

Penny: Maybe there's something in the book that will help.
Leonard: Worth a shot.
Penny: Okay. Let's see, let's see... biting other children?
Leonard: Well, sometimes, but... problem for another day.
Penny: Okay, wait, wait. Here we go. "Let him have ownership of his choices. Allow him to choose from options that are acceptable to you."
Leonard: All, right I'll give it a try. "I can drive you in two hours or you can take an Uber."
Penny: Good. See, now he feels like he has a choice.
Leonard: [his phone chimes] He's gonna take an Uber.
Penny: Wow, it worked.
Leonard: [taking the book] Unless he bites the driver, yeah.

Howard: Okay, I'm gonna extend the wait time and have it poll the A-to-D converter at the top of the loop instead of the bottom.
Amy: That's impressive.
Howard: You think that's impressive, take apart that brain model. [she picks up said model from the tabletop and finds a playing card inside]
Amy: Oh, my god! Three of clubs. That was my card! How did you...?
Howard: I used to make it appear in my pants, but HR said I had stop doing that.

Penny: You sound frustrated, and I'm really proud of the way you're able to state your opinion.
Leonard: Thank you. [realizing what she's doing] Wait, no, no! Don't use that book on me.
Sheldon: Wait, what book?
Leonard: Penny's been using one of Bernadette's parenting books on you.
Penny: What? So has he.
Sheldon: Wh... what makes you think you can treat me like a child?
Leonard: Your shampoo comes in a Big Bird bottle.
Sheldon: That's because the adult shampoo burns my man eyes!

Raj: Hey, what are you working on?
Bernadette: Oh, my god, you're still here?
Raj: Well, of course I'm here. I know what you're going through.
Bernadette: Really? You have a needy Indian man in your house?
Raj: I did, but then he came over here.

Penny: So is this how it's gonna be if we have kids? You're just gonna throw me under the bus?
Leonard: If you spoil them the way you do Sheldon, then yeah.
Penny: Uh, my way was working, okay? I think you're just upset because there are some things I am better than you at.
Leonard: Well, you can't end a sentence with a preposition, so clearly not grammar.
Penny: If you're so smart, was that a smart thing to say?
Leonard: That depends. Before I said it, was sex tonight still on the table?
Penny: No.
Leonard: Then it's fine.

Raj: This is great, the two of us hanging out. Why didn't we think of this earlier?
Sheldon: Agreed. I don't need Amy to watch a movie. I can not hold your hand just as easily.