John Conlan and Lorraine Jenson have signed an oath, pledging to tell the reader only what is true and accurate about their relationship with Mr Pignati - although what this oath is actually worth to the reader, once we find out what unreliable reporters the two actually are, is anybody's guess.
John and Lorraine are both sophomores in high school. They both come from dysfunctional families and both have an appreciation for the satirical. Upon these two things a friendship is born. Lorraine, who is very easily led, spends most of her time with John and another two of their friends, troublemakers and losers, Norton Kelly and Dennis Kobin. When the four kids are bored they prank call random strangers, choosing their numbers out of the telephone book. Lorraine selects a Mr Pignati. She calls him and pretends that she is calling from a charity, collecting money. Mr Pignati is very nice and offers to donate ten dollars. Lorraine doesn't want to go to his house to collect the funds, but as usual she is swayed by her friends. Joh, in particular, can't get there quickly enough. He wants the money for beer and cigarettes. At Mr Pignati's house, they find an older man who is lonely. He invites them inside, donates the promised ten dollars, and shows them his collection of ceramic pigs, telling them that the collection began when he bought his wife a pig so that she could think of him and his last name every time she looked at it. They built the collection together, pig by pig. Now it reminds him of her.
Mr Pignati invites John and Lorraine to go to the zoo with him. They feel that the invitation is slightly odd, but agree to go, and he introduces them to a baboon called Bobo. Bobo is Mr Pignati's best friend and has become the son he never had and the companion he craves. A friendship begins to spring up between the three of them. He provides a family structure that neither of them have at home. Soon they are spending every afternoon at his home. He is fun; he purchases roller skates for himself and for them, and they skate around the house. They also enjoy gourmet dinners, with wine, at his home; he purchases new and exciting foodstuffs and the three of them feast like kings. They are having the time of their lives; that is, until Lorraine confesses to Mr Pignati that they never were collecting for charity. They were swindling him out of his money. Mr Pignati is very hurt and feels betrayed. Lorraine is remorseful, but the revelation takes its toll on him. As they are roller skating around the house, Mr Pignati has a heart attack. He is taken to the hospital, and so that they can visit him, John and Lorraine tell the hospital administrators that they are his children. They offer to take care of his house whilst he is in hospital and he is grateful, telling them that his home is their home in his absence.
John and Lorraine share duties at Mr Pignati's house. They have jumped from one pretense to another; whilst Mr Pignati was home, they were able to pretend that they were all one big, happy family. Now that he is in the hospital and they are taking care of his home, they are pretending that they are making a home, playing grown-ups. Living like a young married couple has the effect of making them feel like a young married couple; they develop feelings for each other that are stronger than the close friendship they have shared up until now.
All pseudo-wedded bliss aside, Lorraine and John are, after all, unsupervised teens, and it isn't long before John comes up with the idea of throwing a party in Mr Pignati's home before he returns on Saturday. He is egged on by his friends, despite Lorraine's reservations. True to form she is swept along by her peer group as well, and soon she is planning the party with as much excitement as John. They invite a few people over for a quick drink, but of course the quick drink with friends escalates until it is out of control, and the house is filled with people they barely recognize who are destroying the house for the sake of destroying it, damaging Mr Pignati's cherished possessions without a second thought. One of Lorraine's friends tries on Mr Pignati's wife's wedding gown and rips it. Norton, who was not actually invited to the party, but gatecrashes anyway with the intention of robbing Mr Pignati, is confronted by John and told to leave. In anger he goest to Mr Pignati's porcelain pig room, and smashes all of his prized collection. John tries to stop him, but he is wearing his roller skates, and is drunk, so cannot. He does however beat him to a pulp afterwards.
The relaxing and happy homecoming to a clean and tidy home that Lorraine and John had originally planned for Mr Pignati has gone by the wayside. He returns on Saturday as the party is still going on. What is worse than finding his home has been destroyed is the fact that he realizes it was his friends John and Lorraine who are responsible. He feels betrayed again, but this time, it is worse, because he believed in their friendship. He calls the police to clear the remainder of the uninvited "guests" out of the house. Lorraine and John fully expect to be arrested, but Mr Pignati, who is a far better friend to them than they are to him, doesn't press charges, and they are free to go. They attempt to talk to Mr Pignati but a cop tells them that they should go home and leave him alone. He is upstairs, in the Pig Room, crying.
John and Lorraine go back to Mr Pignati's house the following day. They find him sweeping up what is left of the ceramic pigs, mostly smashed to smithereens. He seems deflated and beaten, a shadow of himself. The pigs encapsulated all of his most treasured memories of his wife, and the places they had been together in the course of putting the collection together. He feels like he has lost her all over again. Lorraine feels guilty and suggest a visit to the zoo. Mr Pignati agrees. However, the visit is a disaster. Bobo the baboon has died. Mr Pignati is overcome with grief, and the shock of Bobo's passing on top of the recent events in his house are too much. He suffers a second heart attack, goes into cardiac failure, and dies. John unravels and screams out that they have murdered him. He tells Lorraine to leave the scene of Mr Pignati's death so that she is not associated with what has happened; if her mother finds out, she will beat Lorraine as a punishment for being involved in a situation that caused someone to have a heart attack. Both John and Lorraine are filled with remorse, and feel that Mr Pignati would have been better off if he had never met them in the first place. They vow to write the story of their friendship with the generous and special Mr Pignati - the Pigman. This is where we join them, and the novel is created.
