Adult Sheldon explains how a high school is like an academic house of horrors: the cafeteria, with its smell of tater-tots and throw-up; the schoolyard, where one is exposed to bullying by delinquents; but those all pale in comparison to the most horrifying place of all, a place teeming with the sweat and secretions of hundreds of unwashed bodies, the swimming pool. In Principal Petersen’s office, he tells Sheldon that water safety is a required part of his P.E. class, so it’s out of his hands. He suggests Sheldon contact his congressman, but Sheldon admits he did that but the congressman won’t return his calls. Principal Petersen tells Sheldon he is swimming tomorrow.
As John and Connie eat at a diner, he tells her she’s the first ex-girlfriend he’s ever been friends with. Of course, she was also his first ex-girlfriend and his first girlfriend. Meemaw suggests he just think of her as a friend. When John asks her about her new boyfriend, Meemaw declines to discuss her relationship. John thought as friends they would talk about their personal lives, saying her happiness is important to him. Meemaw relents and tells him her boyfriend’s name is Dale and he runs a sporting goods store. Meemaw says they’ve only been out a few times, but so far, so good. John is happy for her and asks if she would like to hear about the other women he’s dating. When Meemaw asks if he’s dating other women, he admits he’s not.
In the garage, George is trying to untangle the Christmas decorations when Mary comes to tell him Sheldon is really worked up about having to swim. George thinks he should learn for his own safety. Mary doesn’t think he’ll ever go near a body of water, but George argues it’ll only be a matter of time before someone throws him in one. When Mary tells George to break the news gently to Sheldon, George wonders why it’s his responsibility. Mary says swimming is a sport and he’s a sports person, but George points out Sheldon is a mama’s boy and she’s his mama. After Mary proposes doing it together, George wants assurances she won’t hang him out to dry. Mary insists they’ll do it as a team, but George isn’t convinced.
Adult Sheldon explains that observation is an important part of the scientific method. Darwin observed the finches, Jane Goodall observed the chimpanzees, and for some reason, Dr. Sturgis wanted to observe Meemaw’s new suitor. At the sporting goods store, Dale sees John staring at him from, so he goes over to see if he can help. John claims to be browsing in the cup section, though he’s evidently unaware what a cup is for.
When Dale walks over to Georgie to ask him to keep an eye on that “weirdo”, Georgie admits he knows John as he’s the guy his Meemaw used to data. Georgie insists he’s really smart, but Dale isn’t sure as he watches John hitting the cup with a ping pong bat. After Georgie goes over to talk to Dr. Sturgis. Dr. Sturgis says an enthusiastic hello, before realizing he’s made a mistake.
Back home, Dr. Sturgis calls Meemaw to tell her about a questionable decision he made in their relationship. John explains that he went to the sporting goods store to check out her new fella. He admits he talked to Dale and even bought an athletic supporter from him to support his genitals. Meemaw suggests he wear it the next time she sees him.
When Mary and George go into the living room to talk to Sheldon, they keep trying to pass the buck to one another. Finally, George tells Sheldon that his mother wants him to swim. After Sheldon storms off to his bedroom in what Missy terms the lamest tantrum she’s ever seen, he tells her he’s being forced to swim tomorrow. Sheldon wonders if it’s time to run away and join a traveling math club, but Missy encourages him to pretend to be sick instead.
That night, Sheldon has a dream about the pool. As he approaches the water, the pool starts to talk to him, asking why he doesn’t like it. When Sheldon says the pool is full of bacteria, pool argues its 3ppm of chlorine means it’s cleaner than his daddy’s plate after Thanksgiving dinner. As Sheldon starts to be convinced, he steps closer toward the pool. As the pool encourages him to get closer and closer, a stream of water jumps out of the pool and grabs Sheldon and pulls him in. Sheldon wakes up in bed fearing a pool monster.
The next morning, Sheldon coughs as he tells his mother he doesn’t feel well. He doesn’t elaborate, saying he just feels awful. Mary mentions that there’s something going around as Billy Sparks got some sort of bug. Mary tells Sheldon he’s staying home today and she’ll go make him some tea. After Mary leaves, Missy welcomes Sheldon to the dark side.
As Missy gets ready for school, Georgie comes to see Sheldon after hearing that he’s sick. After Missy whispers that Sheldon is faking, Georgie closes the door and goes over to ask why. Sheldon explains it’s the swim test. Georgie gives Sheldon some pointers: cough even when Mom isn’t in the room, don’t put the thermometer in the tea, and try coughing up some phlegm.
In the kitchen, after Mary gets off the phone with the school, George tells Mary this all seems a little convenient. When Mary questions whether George thinks Sheldon’s faking, George points out that the swim test is today. After Missy comes in and tells them Sheldon just coughed up something gross, Mary is convinced that Sheldon’s sick and should stay home. George tries to change her mind, but Mary is insistent that her little boy is not a liar.
After a box is delivered to Meemaw’s house, she opens it to reveal a giant cookie with the message, “I overstepped the bounds of friendship. Sorry. -John”, written in icing. Meemaw then gets a phone call from Dale, who’s eating a cookie, wondering why in the hell her ex-boyfriend would send him a cookie.
In the kids’ bedroom, Mary sits on Sheldon’s bed as she takes his temperature. Mary’s words that her little boy is not a liar ring in Sheldon’s head. Mary is happy he doesn’t have a temperature, so she asks if he wants to get come comfy on the couch and watch his Star Trek tapes. A glum Sheldon says no thank you. Mary knows what to do to make him feel better, so she sings him Soft Kitty to him. As Mary sings, Sheldon starts to hear different lyrics, accusing him of being a liar.
Meanwhile, at the school, word spreads about Sheldon being out sick. Coach Wilkins thinks he’s being a baby, but Mr. Givens, Ms. Ingram and Mrs. MacElroy have much more positive reactions to Sheldon’s absence.
Back home, Mary tells Sheldon she’s going to the grocery store for ingredients so she can make him soup. Adult Sheldon says after lying to his mother, the guilt was more than he could take and he had to make things better. He could confess and break his mother’s heart, or he could turn his lie into the truth and actually get sick. Sheldon jumps out of bed, puts his slippers on, and rushes across the street to see Billy Sparks. After Billy explains that he’s got a cold, Sheldon offers to shake his hand. Billy is reluctant as his mom told him that’s how germs are spread, so Sheldon grabs Billy’s hand and rubs it over his face before running home.
Later that day, Mary is making soup in the kitchen when George and asks if it’s for her “patient”. After Mary insists Sheldon is still under the weather, George mockingly acts concerned. Mary admits Sheldon isn’t running a fever and doesn’t have a sniffly nose, but she does point out that he couldn’t bring himself to watch his Star Trek show earlier. When George facetiously suggests calling an ambulance, Mary doesn’t think he’s funny. George insists Sheldon isn’t sick either.
As they toast at a bar, Dale warns Meemaw not to fill up on snacks as they’ve both got giant cookies to finish. After Meemaw apologizes for all that stuff with John, Dale wonders how she met that guy. Meemaw says John’s a very sweet man and explains that he is Sheldon’s college professor. After Dale mocks him for being “smart, short and weird”, Meemaw says that’s enough. Dale won’t let go and asks Meemaw whether she feels like she’s dating a supermodel now.
Back home, as Sheldon reads a Batman comic in bed, Mary comes to check on him and notices he hasn’t touched his soup. Sheldon says he wasn’t hungry. When Mary asks if he’s feeling any better, Sheldon says no. After she leaves, Sheldon starts to hear the voice of Batman coming from his comic. Batman tells him he should be ashamed of himself. Sheldon argues he was only trying to avoid the pool, but Batman says he is in a pool now, a pool of his own deceit. Batman says his mother were alive, he’d never lie to her and he’d always eat her soup.
At the restaurant, Dale tells Meemaw about his grandson’s baseball game where he tripped face first, lost a tooth and still won the game. Dale gets to the punch line: two days later he found the tooth in the bathroom. Meemaw is unimpressed. When Dale asks her if there is something wrong, Meemaw says there is. She doesn’t like the way he’s been talking about John. Dale argues he was just joking around, but Meemaw didn’t like it. Dale can’t see why he’s the bad guy when her “weirdo” ex came sneaking around. Meemaw tells Dale he doesn’t get to call him a weirdo. Meemaw says her and John are friends, so if Dale doesn’t stop making fun of him, they’ll have a problem. Dale is excited by the idea of being on Meemaw’s naughty list.
As Mary cleans up in the kitchen, Sheldon goes to tell her the truth that he wasn’t sick and was just trying to get out of swim practice. After Sheldon says he feels terrible about lying to her, Mary says he should feel terrible. Helpfully, Sheldon mentions how Georgie and Missy taught him how to fake it. Mary tells Sheldon he should not have lied as it’s always wrong, but he made up for it by telling her the truth. When Sheldon asks if she forgives him, Mary says she does, but she needs a favor. As far as his father is concerned, Sheldon was sick. Sheldon questions whether that’s lying, but Mary says, “Honestly, no.”
The next day, Sheldon returns to school and is prepared for the pool, wearing a blue swim cap, goggles and a nose plug, and yellow cleaning gloves on his hand. Adult Sheldon explains that like Batman, he suited up and faced his fears, by doing a doggy-paddle along the shallow end of the pool. Regarding the pool sanitation, it turns out he was right. The pool was teeming with germs. Only, he was the one who put them there. As it happens, he did get sick from Billy Sparks. In turn, he created a small epidemic taking down 128 students, four teachers, and one principal. But it didn’t store there, he also infected his mother, father, sister and brother, Meemaw, and her friend Dale. Luckily for Dr. Sturgis, the newly established boundaries of friendship kept him healthy, and his recently acquired cup helped when he crashed his bike into some garbage cans.