To discover who would be most qualified to be best man and maid of honor at their wedding, Sheldon and Amy subject their friends to a series of secret experiments. Also, Penny realizes her true feelings about Amy.
Driving over to Wolowitz's Amy asks Sheldon not to discuss their wedding plans since Amy hasn't decided on a maid of honor. They decide on code words yo use in case they want to direct the topic of discussion away from their wedding. Sheldon has catamaran while Amy chooses pretzels.
At Howard and Bernadette's Howard and Raj are installing a baby gate while they are baby proofing his house. Penny wonders why they didn't baby proofed the liquor cabinet. Howard tells Amy that Bernadette would be glad to be her maid of honor to return the favor. Amy then asks Sheldon to tell his pretzel story. Sheldon keeps messing it up and then tries to leave, but can't because the front door was baby proofed.
Amy walks into their apartment with an arm load of bridal magazines that Bernadette gave her making her aid of honor decision even harder. Sheldon's mother wants Sheldon to use his brother George as his best man. He doesn't want to disappoint her again since he rejected her savior and her LinkedIn invitation. Amy wants to know how to make these decisions without hurting her friends. Sheldon suggest that they take the emotional component out of the process and let their data make the decisions. Amy describes it as make hurting each other's friends without taking responsibility. "Me Likey," she exclaims. They plan on breaking down the wedding party jobs into specific functions and test their friends as to who does them best.
Later in apartment 4A, Leonard announces that he is writing a book. It about a brilliant physicist who solves crimes using science. No, it's not about Sheldon. Their dinner contained the wrong type of rice that Howard called about thus getting his points for handling a catering crisis. Next Sheldon asks for a toast and them asks for someone to make one waiting patiently.
Later Penny walks in on Shamy to bring a sewing kit they asked for, very promptly getting high marks. They claim to need the kit since Sheldon split his paints bending over. Penny tells him he'll be sore tomorrow as she leaves. Penny got fifteen points, while Bernadette is shipping them a sewing kit through Amazon. Then Sheldon suggests that they do not specify the roles by gender and test everyone for every job. So they might have a best woman and a gentleman of honor.
Loyalty test: Amy tries to confide in a secret to Raj about Howard who will have nothing to do with it. Sheldon is bringing a meal to bedridden Bernadette and tells her a secret that she can't tell anyone including Howard. She agrees. Sheldon can control Leonard's thermostat with his phone.
Getting to the church on time: Sheldon rushes into Leonard and wants to immediately go to the train store in Arcadia. Leonard tells him to see a doctor.
How well do out friends know us?: Amy talks to Penny about her favorite Aunt who Penny does seem to know about.
How do they deal with cold feet? Howard gets tested by Sheldon on whether he should buy a Swamp Thing statue.
Penny walks in on Leonard who is working on a brain teaser on a seating chart arrangement which he finds fun. Penny received the same puzzle from Amy and threw it away. Raj and Howard come in arguing about the same puzzle. Howard thinks that they are acting strange, but Leonard thinks that they were always that way. Raj also had to drive Sheldon all the way to the Arcadia train store and he didn't even go in. All four of them were given plastic rings that they were told to hold onto.
Sheldon and Amy are tallying up results when the gang breaks in on them demanding to know if they are testing them to be in their wedding. "Yes/No!" Leonard tells him that he didn't even want to be his best man. Howard admits that he figured out that they were being tested and he gets extra points for it.
Sheldon enters the comic book store as Stuart offers to sell him a cappuccino which someone had left. Sheldon mentions that no one wants to be his best man and that it might have to use his stupid brother. Stuart offers to do it and Sheldon accepts. Stuart has never been called the best anything and he also gets a present from the groom.
In the cafeteria, Leonard is still working on the seating puzzle. Sheldon comes over to apologize saying that he violated their trust. He tells them that Stuart is his best man and they are still all invited to the bachelor party at Costco. Leonard tells him that its his wedding and he should pick whoever he wants and not to worry about anyone else. Sheldon has been training for this all his life.
Leonard comes in finding Penny fixing Mac and nothing since she spelled the cheese packet. He tells Penny about Sheldon's apology and that he is now Sheldon's best man. He adds that Amy is her best friend and that she'll also get chosen. Penny objects that they aren't twelve anymore even though they talk all the time, see each other all the time and Amy is always there for her--OMG, she realizes that Amy IS her best friend. Then she gets pissed that her best friend didn't ask her to be her maid of honor.
Howard is telling Amy that despite was she did was wrong and cruel, Bernadette finds it oddly appealing. If Amy calls her, she'll do be anything in the wedding party. Penny comes storming in saying that rushes to hug Penny ecstatically shouting, "BESTIE!!"
At Wolowitz's Sheldon apologizes to Stuart, but he was best man for two whole days. Sheldon offers him the job of flower girl until they remind him that they have Halley. Howard hasn't yet told Bernadette that she isn't going to be maid of honor. Amy volunteers which is fine with Penny. Amy reminds Penny that as maid of honor, she should try and make the bride's life easier. Penny begrudgingly says "Fine", but first wants Howard to unlock the liquor cabinet.
- Guest starring:
- Teleplay: Steve Holland, Eric Kaplan & Andy Gordon
- Story: Maria Ferrari, Tara Hernandez & Jeremy Howe
- Title Reference: To be entered.
- Taping date: December 5, 2017
- This episode was watched by xx.xx million people with a rating of x.x (adults 18-49).
- Total viewers including DVR users xx.xx million.
- The Big Bang Theory was ranked #x for the week ending xx January 2018.
- This episode aired in Canada on January 4, 2018.
- Caroline Preece at Den of Geek! - When Amy reveals that she’s still in the process of choosing a maid of honor for the wedding, she asks Sheldon to change the subject should it come up in conversation with their friends. He somehow manages to throw them off the scent despite some close calls, and the couple later decide to use detailed metrics to decide who should be in the wedding party. This is of course pretty arbitrary because, as the audience, we know that Sheldon would never choose Raj or Howard to be his best man, and Amy has been in love with Penny for multiple seasons now...It’s particularly charming when the two of them can be as goofy and terrible as each other, like when Amy rejoices in the idea that she can hurt her friends’ feelings without taking on any of the responsibility. It’s also a testament to how thoroughly quirky the couple are that none of their friends twig until the last minute. 
- In "The Love Car Displacement", Amy announced that Penny was her best friend or "bestie". In this episode, Penny realized through their interactions together and supporting each other, that Amy is her best friend. When she told Amy and complained that she should be her maiden of honor, Amy exploded in joy and hugged her.
- Leonard is going to be Sheldon's best man.
- Penny and Bernadette are both mentioned as maid of honor possibilities, but since they are both married they should be the matron of honor.
- Amy is very happy the pretty popular girl admits that she is her best friend.
- Sheldon: You know, I don't know how I feel about all this baby-proofing. If Halley can't teach herself to walk down the stairs, then maybe that's nature's way of saying the Wolowitz line ends here.
- Sheldon: My mother is pushing for my brother, Georgie, to be my best man, and I hate to disappoint her again. I already rejected her savior and her LinkedIn invitation.
- Sheldon: So as to not upset any of you further, I've asked Stuart to be my best man, and he's agreed. You're all still invited to the bachelor party. Uh, he's thinking Costco and the theme is browsing.
- Leonard: Hey, what you making?
- Penny: Uh, well, I spelled the cheese packet so we’re having mac and nothing.
- Leonard: Oh. Well, I’ll just have the mac. Nothing gives me gas.
- Penny: Why are you in such a good mood?
- Leonard: I just talked to Sheldon. He apologized for the tests and asked me to be his best man.
- Penny: Uh, great after all you’ve done for him, he should’ve asked you.
- Leonard: And Amy’s you’re best friend. I’m sure she’ll come around to her senses and pick you.
- Penny: Okay, she’s not my best friend. We’re not twelve. If she wants Bernadette to be her maid of honor I don’t really care.
- Leonard: Sounds like you care.
- Penny: No, I mean it’s just annoying. You know we talk every day. We see each other all the time. She’s always there for me, basically-Oh my God. Amy’s my best friend.
- Leonard: You okay?
- Penny: No, my best friend didn’t ask me to be her maid of honor. I’m pissed.
[In apartment 4B, immediately afterwards]
- Howard: So bottom line, what you did was wrong and cruel which the mother of my child finds oddly appealing.
- Amy: So she still wants to be my maid of honor?
- Howard: Maid of honor, hit woman, whatever you need. Make the call.
- Penny: [Storms in.] Look, I know this is your wedding and you can do whatever you want, but if you think anyone but me is gonna to be your maid of honor then you’re an idiot since you are my best friend.
- Amy: Too late, Bernad..Bestie! [Extremely happy.]