The spring of their sophomore year of high school, Lorraine Jensen and John Conlan sign an oath vowing to tell the truth—and only the truth—about their experiences with Mr. Angelo Pignati, “The Pigman.” What follows is a first-person confession, told from Lorraine and John’s alternating perspectives, of the previous months they spent getting to know Mr. Pignati, who has since died.
John is a handsome, outgoing jokester who regularly orchestrates pranks to get a rise out of people at school. Lorraine, meanwhile, is shy and reserved. She was lonely when she first moved into John’s neighborhood last year, but now they’re each other’s best friend. Still, Lorraine grouses about John’s apparent need to wear unconventional clothing, swear, drink alcohol, and smoke cigarettes, though she hypothesizes that he probably does these things to rebel—Lorraine reads a lot of psychological articles and is constantly analyzing people in her life. And John comes from a dysfunctional household: his dad (whom John calls “Bore”) is a mean recovering alcoholic who introduced John to drinking at a young age, and his mother (whom John calls “The Old Lady”) is too timid and anxious to defend John against his father and support him.
Lorraine’s situation isn’t much better: Lorraine’s father cheated on Lorraine’s mother when she was pregnant with Lorraine and then abandoned the family and died not long after. Lorraine’s mother struggles to raise Lorraine on her own on a nurse’s salary. Her husband’s infidelity led her to develop a hatred for men, boys, and sex, and she takes out a lot of her stress and anger on Lorraine, constantly criticizing her appearance, berating her, and even beating her. As a result, Lorraine has poor self-esteem and rarely acts on her instincts. For instance, in retrospect, Lorraine believes that she received numerous “bad omens” foreshadowing Mr. Pignati’s death but chose to ignore them.
Mr. Pignati first comes into John and Lorraine’s life by accident. The teens are making prank phone calls with Dennis Jobin and Norton Kelly, two “really disturbed” classmates of theirs. Lorraine randomly selects Mr. Pignati’s number out of a phonebook, pretending to be calling from a local charity when Mr. Pignati picks up. Lorraine instantly detects the loneliness in Mr. Pignati’s voice—it’s clear he’s desperate for someone to talk to. Things escalate, and John arranges for the two of them to go to Mr. Pignati’s house, pretending to be charity workers, to pick up Mr. Pignati’s 10 dollar “donation” to their fund.
John and Lorraine arrive at Mr. Pignati’s house and find Mr. Pignati to be a cheerful, talkative elderly man. He invites them inside, pours them glasses of homemade wine, and talks to them about his love of zoos and his wife Conchetta, who he claims is out of town visiting relatives. When he talks about Conchetta, he momentarily looks like he’s about to cry. Mr. Pignati also shows them his prized collection of pig figurines. He asks the teens if they’d like to go to the zoo tomorrow, but they’re hesitant.
After talking with Mr. Pignati awhile, Mr. Pignati gives John and Lorraine his “donation,” and the teens excuse themselves. John uses Mr. Pignati’s check to buy beer and cigarettes. Lorraine feels guilty about taking advantage of Mr. Pignati, but it doesn’t bother John. Lorraine returns home and has an argument with her mom. Afterward, needing something to cheer her up, she calls up John and tells him she’d like to go to the zoo with Mr. Pignati tomorrow after all.
The next day, the teens cut class and meet Mr. Pignati at the zoo. Mr. Pignati buys them peanuts and then takes them to the monkey house to introduce them to his friend Bobo, a mean, ugly baboon. Mr. Pignati, unperturbed by Bobo’s unfriendliness, smiles and throws peanuts into Bobo’s cage.
Time passes. John and Lorraine spend their days hanging out in a local cemetery and at Mr. Pignati’s house. They eventually grow close to the old man and come to think of him as one of their favorite people, though they don’t yet come clean with him that they’re high school students, not charity workers. One day, while at Mr. Pignati’s house, John finds some papers from a local funeral home and discovers that Conchetta isn’t away visiting relatives—in fact, she recently died. John shares this information with Lorraine, but they decide not to tell Mr. Pignati what they know just yet.
One day, Mr. Pignati, who enjoys eclectic, foreign delicacies and other fancy foods, takes the teens to the department store Beekman’s in Manhattan for a shopping spree. They also buy roller skates for the three of them.
About a month after John and Lorraine start hanging out with Mr. Pignati, Norton Kelly invites John to the cemetery for a beer. Norton asks John why he spends so much time with Mr. Pignati—does he have anything in his house worth stealing? When John refuses to answer, Norton insinuates that he’ll rob Mr. Pignati. In response, John calls Norton “Marshmallow Kid,” a nickname kids gave Norton after he was caught shoplifting marshmallows from the local supermarket. Then John storms off, inwardly vowing to hurt Norton if he does anything to Mr. Pignati.
Sometime later, John and Lorraine are at Mr. Pignati’s house, and Mr. Pignati seems especially blue. The teens decide it’s time to come clean about their real identities, and they reveal that they’re actually high school students. In response, Mr. Pignati admits that Conchetta isn’t actually visiting relatives—she’s dead, and Mr. Pignati misses her terribly. The teens comfort Mr. Pignati. To lighten the mood, John puts on his roller skates and zooms around the house. Lorraine and Mr. Pignati join him. But in the process, Mr. Pignati overexerts himself and has a heart attack. John calls an ambulance.
The next day, John and Lorraine cut class to visit Mr. Pignati at the hospital. He’s doing much better but will have to remain at the hospital awhile longer—in the meantime, he tells the teens they can continue to hang out at his house. Lorraine and John return to Mr. Pignati’s house that evening, and Lorraine makes dinner. They dress up in Mr. Pignati’s and Conchetta’s clothing and goof around. John thinks Lorraine looks genuinely beautiful in one of Conchetta’s old dresses.; he chases Lorraine into Mr. Pignati’s bedroom and kisses her, which catches them both off guard.
Later, Lorraine calls up a nurse at the hospital who tells her that the earliest Mr. Pignati would be released is Saturday. That Friday, Lorraine and John return to Mr. Pignati’s house. Things have been weird between them since their kiss earlier that week. Despite Lorraine’s protests, John invites a bunch of their classmates over for a party that night. Around 40 kids show up; there’s live music, dancing, and lots of drinking. Norton arrives later, upset that he wasn’t invited. Sometime later, John hears sounds coming from the room where Mr. Pignati keeps his pig collection. He looks inside and finds Norton destroying all the pigs. Overcome with rage, John punches Norton in the face; a fight ensues. Just then, Mr. Pignati arrives home.
The police escort John and Lorraine home, telling them they’re lucky that Mr. Pignati isn’t going to press charges. When they reach Lorraine’s house and explain things to Lorraine’s mother, she hits Lorraine, scolds her for lying, and then breaks down crying. Lorraine hugs her mother, guilty about all she has put her through.
John calls Lorraine the next morning and says that his parents hardly reacted when the police brought him home. Bore told John he was going to make him see a psychiatrist, but John doubts this will actually happen. John and Lorraine meet up later that day and call Mr. Pignati from a pay phone to apologize for breaking his trust. He sounds sad but agrees to meet them at the zoo.
When Mr. Pignati arrives at the zoo, he looks tired and sad but seems happy to see Lorraine and John. They buy some peanuts and make their way to the monkey house to see Bobo. But when they arrive, Bobo’s cage is empty, and a zookeeper informs them that Bobo has died. Hearing this, Mr. Pignati has a heart attack and dies. Lorraine runs out of the monkey house while John stays behind to be with Mr. Pignati’s body and deal with first responders. Afterward, John finds Lorraine outside, sitting on a bench, and sits down beside her. Inwardly, John considers how all their consequences have actions. He and Lorraine can’t blame anyone for their problems—only they are responsible for what happens to them and how their actions affect others.