Note: The narrative is non-chronological; its structure is meant to follow the pattern of a Sierpinski triangle, a mathematically-generated pattern of triangles inside triangles.
At Hal Incandenza’s admissions interview at the University of Arizona, the university’s deans are concerned that he may have cheated on his highly impressive (but uneven) application. Hal tries to explain that the application is genuine, but the deans think he is having some kind of seizure or psychotic episode, and he is taken to the hospital. Hal always had difficulty communicating with his father, James, who is now dead. Their conversations would end in Hal choking. Hal shares a bedroom with his older, disabled brother Mario at the Enfield Tennis Academy in Enfield, Massachusetts. Hal speaks to his other brother Orin on the phone, but the line cuts out.
The medical attaché to Prince Q——, the Saudi Minister for Home Entertainment, wants to relax at the end of the day by watching a film cartridge. He finds an unmarked cartridge that has been sent to him in the mail and puts it in the Teleputer (TP) to watch. Orin is an NFL player who has been having nightmares about his mother, Avril. Hal has developed a secret marijuana addiction, and spends much of his time secretly getting high in the Pump Room at E.T.A.
Don Gately is a 27-year-old narcotics addict who robs houses to finance his addiction. He breaks into the home of Guillaume DuPlessis and accidentally kills him by gagging him when DuPlessis is ill with a cold and cannot breathe through his nose.
James Incandenza was the first Headmaster of E.T.A.; following his death, his brother-in-law Charles Tavis took over. Charles and Avril had an affair and Charles is likely Mario’s true father. Both James and his father, James Sr., had been talented junior tennis players. James Jr. went on to gain a PhD in optical physics and then began making avant-garde films. Avril is from Québec, and her marriage to James allowed her to secure an American visa after difficulties she encountered due to her youthful involvement with Quebecois separatists. James was 54 when he killed himself.
Kate Gompert, who has just been hospitalized after her fourth suicide attempt in three years, tells her doctor about the unbearable pain of her depression and how this intersects with her marijuana addiction. Meanwhile, the medical attaché hasn’t shown up for work, so Prince Q——’s personal assistant goes to his house to see what’s wrong. The assistant himself doesn’t come back, and neither do two security guards from the Saudi embassy or a pair of Seventh Day Adventists who attempt to deliver a pamphlet to the attaché’s house. This whole group of people now stands staring at the attaché’s TP.
Rémy Marathe, a Quebecois wheelchair user and member of the separatist organization A.F.R. (the Wheelchair Assassins), meets with O.U.S. operative Hugh Steeply in Arizona. Hugh is undercover and in disguise as Helen, a female journalist. Marathe is either a triple or quadruple agent, as it is unclear whether he is actually betraying the A.F.R. or not. The two discuss a lethal film cartridge called the Entertainment that has been sent to the attaché. The A.F.R. want to use the cartridge as a weapon of mass destruction in order to force the secession of Quebec from both Canada and O.N.A.N. (the Organization of North American Nations). The creator of the Entertainment is from Boston, which is the nearest American city to the Great Concavity, a toxic wasteland that was “gifted” to Canada by the U.S. during the formation of O.N.A.N.
Ennet House Drug and Alcohol Recovery House was founded by an addict who believed in such an extreme form of submission to recovery programs that he made residents eat rocks to prove their commitment to sobriety (this practice was eventually banned). An E.T.A. student called Michael Pemulis travels into Boston to buy DMZ, an infamously powerful drug nicknamed “Madame Psychosis” after the host of a cult radio show on M.I.T.’s student radio station, WYYY. While the show is being recorded, Madame Psychosis sits behind a screen in the studio and smokes.
Ennet House sits on the site of the Enfield Marine Public Health Hospital, which is only a brief walk from E.T.A. Kate is now a resident at Ennet House, and Don Gately is a residential staffer. At E.T.A., Hal, Pemulis, and their friend Trevor Axford plan their DMZ trip, knowing they will need to set aside 36 hours for the experience.
Joelle van Dyne plans to kill herself via overdose at her friend Molly Notkin’s party. Joelle and Molly met as PhD students in the M.I.T. department of Film & Film-Cartridge Theory. Joelle is addicted to crack cocaine, and although she doesn’t enjoy using the drug anymore, she doesn’t feel like she can stop. After attempting her overdose, she throws up into Molly’s bathtub.
Orin calls Hal and tells him that he is being profiled by a journalist (presumably Helen Steeply). The brothers discuss the aftermath of James’s suicide. Hal was the one to find their father’s body; he had put his head inside a microwave. During Orin’s freshman year of college, he fell in love with a sophomore baton-twirler (Joelle) whom he nicknamed P.G.O.A.T. (Prettiest Girl Of All Time), and switched from varsity tennis to varsity football in order to be around her. Joelle and Orin started dating, and Joelle starred in some of James’s films.
Mario was born very prematurely, with a range of physical and mental disabilities. Every year on “Interdependence Day,” E.T.A. students play a complex game of their own invention called Eschaton. This year, the game descends into a massive fistfight, to the dismay of Hal and the other older students. Having failed to kill herself, Joelle checks into Ennet House. Gately is attracted to her even though she wears a veil over her face at all times. Back at E.T.A., Mario puts on his annual screening of a film he made about the formation of O.N.A.N. using puppets.
In Arizona, Marathe and Steeply have a debate about individual freedom versus collective benefit. Madame Psychosis (Joelle) goes missing from her radio station, and Mario—who is a fan of her show—is distraught. Steeply tells Marathe about a Canadian biomedical experiment in which animals were given a lever to press that produced intense feelings of pleasure through electrodes in the brain. The animals died in the experiment, yet when details of the experiment were leaked, hundreds of young, healthy volunteers attempted to sign themselves up as test subjects.
Back in Boston, members of the A.F.R. arrive at a cartridge rental store belonging to the small-time Quebecois separatist brothers Lucien and Bertraund Antitoi, searching for the master copy of the Entertainment; however, the copy they find is read-only. One of them kills Lucien by shoving a broken broom handle down his throat.
Following the Eschaton fiasco, all students at E.T.A. are disciplined, though the older ones receive the harsher punishment. Hal and his friends are also told they must take a urine test. At Ennet House, new resident Randy Lenz continues to take small amounts of cocaine, and also starts to inflict violence on animals. Rodney Tine, Chief of the O.U.S., is doing everything he can not only to track down the master copy of the Entertainment, but to stop the highly curious President Johnny Gentle from viewing the Entertainment himself to see what it is like.
Back at E.T.A., Pemulis goes into Avril’s (door-less) office and catches her in the midst of a sexual roleplay scenario with E.T.A. student John Wayne. Lenz and another Ennet House resident, Bruce Green, are walking home from an AA meeting. Lenz is high on coke and won’t stop talking, but Green is distracted by his own sad childhood memories. Suddenly, Lenz grabs a dog and stabs it.
Meanwhile, Orin is in a hotel having sex with his latest “Subject,” a Swiss hand model, when a man in a wheelchair knocks on the door and requests that he answer some questions for a survey. Orin complies and the man asks him about what he misses or feels nostalgic about. However, the conversation doesn’t last long, as the man sees that Orin is otherwise occupied.
Outside Ennet House, a fight breaks out between Lenz and a group of Canadian men, and despite not knowing why the fight broke out, many other residents join in. In the scuffle Gately gets shot by one of the Canadians. At E.T.A., it is revealed that Hal and the others’ urine test is not for another 29 days. Hal has quit smoking weed and feels like an entirely different person; the other students wonder what is wrong with him.
Helen Steeply arrives at E.T.A. hoping to interview Hal for her “profile” on Orin, however E.T.A. staff are reluctant to let her speak with him. Something goes terribly wrong in Hal’s game against Ortho Stice and he loses his 2nd place rank at E.T.A.
Kate and another Ennet House resident, Ruth van Cleve, are walking near Inman Square when an addict called Poor Tony Krause robs their purses, injuring Kate in the process. Hal watches one of his father’s film cartridges and feels disappointed by the ambiguous, inconclusive ending, which he finds embarrassingly heavy-handed. The A.F.R. strategize about their next move, wondering if they should torture Joelle and/or members of the Incandenza family to help them find the master copy of the Entertainment.
Marathe arrives at Ennet House pretending to be a Swiss heroin addict seeking treatment. The Ennet House Director, Pat Montesian, agrees to house him. He is unsure whether he should betray the A.F.R. or not; he wants to pursue the course of action most likely to help his wife, Gertraude, who is severely disabled, comatose, and in need of urgent medical treatment.
Hal finally opens up to Mario, confessing to his drug use and admitting that he’s feeling lost and confused about what to do. He feels guilty as he knows that Pemulis will be used as a scapegoat for the issue of Substance abuse at E.T.A. At a jazz club in Inman Square, Kate and Marathe are getting drunk together. Kate, who is relapsing, accuses Marathe of not really loving his wife before passing out. Hal goes to Ennet House seeking treatment. Molly is interrogated by O.U.S. operatives. She explains that Madame Psychosis/Joelle’s real name is Lucille Duquette and that she is from Kentucky. Joelle’s father was sexually attracted her; after he finally confessed to this, Joelle’s mother attempted to pour acid on him but ended up pouring it on Joelle instead, disfiguring her.
Pemulis is told that he is being expelled from E.T.A., news he takes rather calmly. Hal goes to an NA meeting and is shocked by what he sees there. Gately is taken to the hospital, where he tries to explain that he can’t be given narcotics because he is an addict. However, he is unable to communicate. Various Ennet House residents and staff visit him, but none seem to notice or care that he cannot talk back to them.
In a surreal dream sequence, Gately is visited by a “wraith” who is revealed to be the spirit of James Incandenza. During its visit, the wraith explains that it made the Entertainment as a desperate attempt to communicate with Hal. Joelle also visits, although this is later revealed to be a dream. Gately has increasingly exasperated and panicked encounters with doctors trying to give him narcotics, but is still unable to properly express himself. Gately’s drug use began when he was a teenager, and eventually led to him being kicked out of high school. He then worked with a Dilaudid addict named Facklemann collecting bets for a bookmaker.
Joelle tells Hugh/Helen Steeply that a master copy of the Entertainment probably doesn’t exist, and if it does it is buried with James. Hal watches a disturbing snuff-film-like work by his father. Meanwhile, Orin has been imprisoned in a glass cage by the Swiss hand model, who turns out to be Luria P——, and M. Fortier. Luria pours cockroaches into the cage in order to force Orin to reveal the location of the master copy of the Entertainment. (This seemingly confirms that it is Orin who has been sending copies to people such as the medical attaché.) Orin breaks down and agrees.
Gately recalls the gruesome moment when Facklemann was taken down by a group of henchmen acting on behalf of Sorkin, a vengeful bookie who was scammed by him. The henchmen sewed Facklemann’s eyes open and forced him to watch a film cartridge, while giving Gately an extremely strong and pleasant drug called Sunshine. Gately passes out from the Sunshine and wakes up on a beach, lying on “freezing sand.”