Chase: Parents aren't doing or dosing this kid.

House: How would you know that? Kid can't talk. Why do you think I took this case? He's not going to give away the ending.

―Lines in the Sand

Lines in the Sand is a 3rd season episode of House which first aired on September 26, 2006. House is drawn to the case of an autistic boy, apparently only for the reason that the patient can't communicate well enough to give House any clues as to his condition. However, it's House's social skills that are soon at issue when he insists his blood-stained carpet be returned to his office. Meanwhile, a 17-year-old patient starts finding House irresistible.

A 10 year-old autistic boy named Adam Kelvey is communicating with his father using pictograms. He quickly tires of it and starts drawing wavy lines with chalk. His parents start arguing about his condition and habits when Adam starts coughing, then screaming. He's taken to Princeton-Plainsboro for examination.

House takes the case, ignoring remarks from Foreman that the patient is screaming because of his autism. Cameron is astounded that House believes the parents when they say something is wrong, but House notes that his parents have been caring for him constantly and this is the first time that they've brought him to the hospital. He orders tests and an environmental scan. He jokes about how difficult it will be to perform a scan on an autistic young boy.

House storms to Cuddy to demand she put the carpet-stained with his blood from the attack on his life- back in his office. House tells her he won't use his office until the carpet is returned. When Cuddy resists, he starts shouting "Attica! Attica!", but Cuddy remains unmoved.

When Foreman goes to test the patient, his father tells them to wait until Adam finishes a level on his video game. Foreman, impatient, attempts to yank Adam's video game console out of his hands, causing the latter to go wild. Adam is restrained in order to get him into the scanner.

Chase and Cameron go to search the patient's house. They discuss why the parents would give up their lives to care for their son.

The tests come back normal, and House is working in the clinic with his team to stay out of his office in order to defy Cuddy. Cuddy comes in and tells House his behavior isn't going to make her change her mind about the blood-stained carpet. House orders his team to take a fecal smear. However, as the team goes to do the fecal smear, Adam starts suffer from a pleural effusion.

House retreats to Wilson's office to do his differential, but as he orders an echocardiogram and antibiotics, Wilson opens the door to find them there. He stops House from playing with his things. House asks why Wilson never throws anything out, and then drops a thank you gift from a child patient into the trash.

Once again, the patient is frantic while Foreman performs the echocardiogram. House retreats to a conference room. Foreman finds and confirms that the patient has a conduction abnormality. At that moment, Cameron realizes House is not just playing power games, actually does want his bloodstained carpet back. Cuddy enters the conference room and throws the team out. House orders Foreman to do a lung biopsy, but Foreman tricks Wilson into doing it, although Wilson says a lymph node biopsy under the arm is a better idea. Once again, the patient is frantic during the procedure. House manages to anesthetize the patient by taking some of the anesthetic himself. The patient follows suit and is knocked out. The parents are impressed. House says it was only the child imitating him.

House, too, wonders why the parents have invested so much into their child. He expresses envy about how the child doesn't have to worry about social graces. The lymph node biopsy is negative; however, the cells biopsied are liver cells.

House and the team retire into Wilson's office. Cameron thinks the misplaced liver cells might be a sign of cancer. If the cells were damaged, they could travel through the body. However, the patient's liver tests are normal. The only explanation seems to be cirrhosis, but the only way Adam could've gotten cirrhosis would've been his parents giving their son alcohol. House thinks the parents don't want to deal with their son anymore and orders a liver biopsy. House tells Cameron his parents love him unconditionally.

House takes up residence in Cuddy's office. House asks Foreman for the results of the stool sample, but it's normal. Cuddy enters her office and confronts House, but gets him to leave when a phone call informs them that the patient has been taken to the cardiac intensive care unit.

They manage to stabilize the patient, but now the patient's liver is failing. House suspects that Adam might have eaten something that is causing the liver failure. He orders Foreman to take samples from the patient's house.

Foreman finds jimsonweed, which would explain the symptoms except for the screaming. However, if the patient doesn't have jimson weed poisoning, the treatment for it will make him worse. Testing him will take more time than the patient is likely to live. House goes to the patient and asks him what he ate, while holding up the pictures he uses to communicate. The patient grabs the picture of the sandbox and, at the same moment, his eye rotates backwards in its socket.

House calls for the team to meet in the chapel. The team begins discussing the possibilities of why Adam's eye rolled back, which is consistent with jimson weed. Foreman thinks it might be a metastasized microtumor, but if he's right, it would mean removing the patient's eye.

However, just before the operation, House realizes that the squiggly lines the patient has been drawing on his chalkboard are worms in his eye-the only way the patient could communicate the symptom. House examines the patient's vitreous humor and finds the worms. He has a parasitic infection from eating animal feces in his sandbox. The condition can be successfully treated.

Wilson tells Cuddy that House may have Asperger syndrome, a subtype of autism. She doesn't believe him, but he tells her that House took this patient because he reminds him of himself. However, after he convinces Cuddy, he goes to House and tells him it was all a lie-he really is just a jerk. House thinks that the patient will never feel the happiness that neurotypical people feel, and the parents' lack of enthusiasm is due to the fact that they will have to constantly care for the boy for the rest of his life. However, as the family is set to leave, the patient hands House his beloved PSP and makes direct eye contact with House. His parents are ecstatic, since he has never shown that level of emotional connection before.

House returns to his office and his old blood-stained carpet.

Baylisascaris is a common infection in humans and is ubiquitous in the environment. It can develop anywhere there are animal feces as it infects more than fifty different species. It is very easy to contract.

• House's comment "We'll always have Fresno" is a reference to the famous line "We'll always have Paris" from the 1942 classic film Casablanca.
• "Line in the sand" is a common idiom representing a point past which a person will not cross or after which advance would not be acceptable. It has several expressions in this episode: House refuses to let his old carpet be removed, and Cuddy refuses to return it. The patient keeps drawing lines to indicate his condition. The patient contracts his disease in his sandbox. House is seen in Wilson's office, drawing lines in Wilson's miniature zen sand garden. House declines to sleep with Ali. Ali points out the age of consent in New Jersey (18) is arbitrary compared to those in other places (such as Iceland, where the age is 14). An error the episode makes is the New Jersey age of consent is actually 16. Either the writers didn't want the complaints from viewers over making it realistic, or it was a purposeful mistake showing her possibly compromised mental faculties. Or it's a popular misconception, as 18 is the voting age, the average age for graduating high school, and generally considered the threshold of adulthood. 18 is a common age of consent in the United States, such as in California, where the show was produced. Whatever the explanation for the goof, if House knows Ali is incorrect, he's being just mature enough not to "help" her with the truth. Cuddy bars Ali from the hospital premises. Cuddy threatens to fire House, but when she does not, House reminds her that threats that aren't followed up on indicate weakness.
• Attica is a reference to the Attica Correctional Facility, a prison in upstate New York that hosted a riot in 1971. House's chant of "Attica" is from the film Dog Day Afternoon.
• Zen is a school of Buddhism, native to China. The miniature sand garden in Wilson's office were influenced by Zen.
• House throws out a small doctor effigy that Wilson received from an 11-year-old patient, now dead. Visible on one of the upper shelves on the wall perpendicular to Wilson's desk is a deep-sea diver robot. We will get the backstory on this toy and a few other souvenirs in Wilson's office in The C Word.
• "Mel's Diner" was the setting for a popular sitcom from the '70s and '80s, Alice.
• House's dialogue in his final scene with Ali is paraphrased from Casablanca, a 1942 film about two former lovers who re-meet years after she leaves him to join her older husband, who she has just learned has not died. The dialogue is taken from the scene where Humphrey Bogart convinces Ingrid Bergman to leave with her husband.
• This episode is based on a real case from 2005. There, the patient was 7 and suffered similar symptoms before recovering.[1]
• Upon discovering the jimson weed in the patient's back yard, Foreman suggests that he is "tripping on lucy in the sky with cubic zirconium". This is a reference to the Beatles song "Lucy in the Sky with Diamonds" which itself is believed (though denied by the writer, Lennon) to be a reference to the psychedelic drug, LSD.
• When House is playing PSP while laying in Adam's hospital bed, he appears to be playing Frogger: Helmet Chaos.
• Wilson has framed posters for the films Vertigo and Touch of Evil on his office walls.
• Wilson describes Asperger Syndrome as a "mild and rare form of autism", however rates of Asperger Syndrome are estimated by autism.org.uk to be greater than 1 in 100 people.
• House gives a happiness rating Adam's parents are supposed to be feeling/exhibiting now that they can take their healthy (still severely autistic) son home: they should be at a 10 vs their "tepid 6.5" (an 8 would be experiencing a first tongue kiss). House might be paraphrasing and referring back to Meaning when Wilson was trying to impart a psychological framework (which House tried to escape and mock to no avail) for House's struggles with boredom, anhedonia, and accepting gratitude and satisfaction. Wilson began with, "The reason we crave meaning is because it makes us happy. The FIRST Level of Happiness-" before he was cut off. After some googling, this editor has yet to find a Happiness model with 5 (or more?) levels where the 5th is about creation and changing/saving lives, either from a psychology textbook or pop psychology social media post/book.