The author′s note is an integral part of the novel. Unusually, the note describes entirely fictional events. It serves to establish and enforce one of the novel′s main themes: the relativity of truth.
Life of Pi is subdivided into three sections. In the first section, the main character, by the name of Piscine Patel, an adult Canadian, reminisces about his childhood in India. His father owns a zoo in Pondicherry. The livelihood provides the family with a relatively affluent lifestyle and some understanding of animal psychology. Piscine describes how he acquired his full name, Piscine Molitor Patel, as a tribute to the swimming pool in France. After hearing schoolmates tease him by transforming the first name into ″Pissing″, he establishes the short form of his name as ″Pi″ when he starts secondary school. The name, he says, pays tribute to the irrational number which is the ratio of the circumference of a circle to its diameter. In describing his experiences, Pi describes several other unusual situations involving proper names: two visitors to the zoo, one a devout Muslim, and the other a committed atheist, bear identical names; and a memorably 450-pound tiger at the zoo bears the name Richard Parker as the result of a clerical error in which human and animal names were reversed.
Pi is raised a Hindu who practices vegetarianism. At the age of fourteen, he investigates Christianity and Islam, and decides to become an adherent of all three religions, much to his parents′s dismay, saying he ″just wants to love God.″ He tries to understand God through the lens of each religion, and comes to recognize benefits in each one.
Shifting government policies lead to a decision by Pi′s father to sell the zoo and emigrate with his wife and sons to Canada. The second part of the novel begins with Pi′s family aboard the Tsimtsum, the Japanese freighter that is transporting animals from their zoo to North America. A few days out of port from Manila, the ship encounters a storm and sinks. Pi manages to escape in a small lifeboat, only to learn that the boat also holds a spotted hyena, an injured Grant′s zebra, and an orangutan. To Pi′s distress, the hyena kills the zebra and then the orangutan. At this point, Pi learns that a tiger has been hiding under the boat′s tarpaulin: Richard Parker, who had boarded the lifeboat with ambivalent assistance from Pi himself. Suddenly emerging from his hideaway, he kills and eats the hyena.
Frightened, Pi constructs a small raft out of rescue flotation devices, tethers it to the stern of the boat and retreats to it. He begins conditioning Richard Parker to take a submissive role by using food as a positive reinforcer and seasickness as a punishment mechanism while using a whistle for signals. Pi asserts himself as the alpha animal and is eventually able to share the boat with Richard Parker.
Pi recounts various events while adrift in the Pacific Ocean. At his lowest point, exposure renders him blind and unable to catch fish. In a state of delirium, he talks with a marine ″echo″. He initially identifies the voice as Richard Parker having gained the ability to speak, but it turns out to be another castaway, also blinded. The castaway (a Frenchman) tries to come aboard Pi's lifeboat, but is quickly killed by Richard Parker. Later, Pi′s boat comes ashore on a floating island network of algae and inhabited by hundreds and thousands of meerkats. Pi gains strength, but his discovery that the island′s plant life is carnivorous forces him to return to the boat. Two hundred and twenty-seven days after the ship′s sinking, the lifeboat washes onto a beach in Mexico. Richard Parker disappears into the nearby jungle without looking back, leaving Pi heartbroken at the abrupt farewell.
The third part of the novel describes a conversation between Pi and two officials from the Japanese Ministry of Transport who are conducting an inquiry into the shipwreck. They meet him at the hospital in Mexico where he is recovering. Pi tells them his tale, but the officials reject it as unbelievable. Pi then offers them a second story in which he is adrift on a lifeboat not with zoo animals, but with the ship′s cook, a Taiwanese sailor with a broken leg, and his own mother. The cook amputates the sailor′s leg for use as fishing bait, then kills the sailor and Pi′s mother for food, and soon he is killed by Pi, who dines on him.
The officials note parallels between the two stories. They soon conclude that the hyena symbolizes the cook, the zebra the sailor, the orangutan Pi′s mother, and the tiger Pi. Pi points out that neither story can be proven and neither explains the cause of the shipwreck, so he asks the officials which story they prefer: the one without animals or the one with animals. They choose the story with the animals. Pi thanks them and says: ″And so it goes with God.″ The officers then leave him and file a report.