A fictional author travels to India, and there he hears an extraordinary story from a man named Francis Adirubasamy. The author tracks down and interviews the story’s subject, Piscine Molitor Patel, usually called Pi, in Canada. The author writes the rest of the narrative from Pi’s point of view, occasionally interrupting to describe his interviews with the adult Pi.
Pi grows up in Pondicherry, India in the 1970s. He is named after a famous swimming pool in Paris. Pi’s father is a zookeeper, and Pi and his brother Ravi are raised among exotic wild animals. Pi’s tale frequently digresses to explain about zookeeping, animal territories, and boundaries. His father warns him of the danger of wild animals by making Pi watch a tiger eat a goat, but Pi also learns that “the most dangerous animal at a zoo is Man.”
Pi is raised culturally Hindu, but his family is generally unreligious. As a youth Pi becomes devoutly Hindu and then converts to Christianity and Islam. He practices all three religions at once, despite the protests of his parents and the religious leaders. The “Emergency” brings political turmoil to India and Pi’s parents decide to sell the zoo and move the family to Canada. They board a Japanese cargo ship called the Tsimtsum, traveling with many of the zoo animals.
There is an explosion one night and the Tsimtsum starts sinking. Pi is awake at the time, and some sailors throw him into a lifeboat. The ship sinks, leaving no human survivors except for Pi. Pi sees a tiger, Richard Parker, and encourages him to climb aboard. Pi eventually finds himself on the lifeboat with a zebra, a hyena, and Orange Juice the orangutan. The hyena kills the zebra and eats it. The hyena then fights and kills Orange Juice. Pi notices that Richard Parker is still in the boat, hiding under a tarpaulin. Richard Parker kills the hyena, leaving Pi alone with the tiger.
Pi makes a raft for himself and finds supplies in the lifeboat, and he sets about marking his territory and “taming” Richard Parker using a whistle. Pi kills and eats fish and turtles, filters seawater, and collects rainwater. Pi and Richard Parker each occupy their own territory in the lifeboat and live peacefully, though they are constantly starving.
Pi loses track of time as months pass. He remembers episodes like seeing a whale, experiencing a lightning storm, and watching a ship pass by. Pi goes temporarily blind and hears a voice talking to him. At first he thinks it is Richard Parker, but then he realizes it is another castaway who is also blind. The two discuss food and then bring their boats together. The castaway attacks Pi, intending to kill and eat him. Richard Parker kills the castaway.
Later the boat comes to a mysterious island made entirely of algae and inhabited by thousands of meerkats. Pi and Richard Parker stay there for a while and recover their health. One day Pi finds a tree with human teeth as its fruit, and he realizes that the island is carnivorous. Pi decides to leave with Richard Parker. Finally the lifeboat washes up on a beach in Mexico. Richard Parker disappears into the jungle without looking back, and Pi is rescued by some villagers.
The last section is a transcript of an interview between Pi and two Japanese officials who are trying to figure out why the Tsimtsum sank. Pi tells them his story, but they don’t believe him. He then tells them a second story, replacing the animals with humans – in this version Pi is on the lifeboat with a French cook, a Chinese sailor, and his own mother. The sailor dies and the cook eats his flesh. The cook later kills Pi’s mother, and then Pi kills the cook. The officials are horrified, but they believe this story. They note that the hyena is the cook, the zebra is the sailor, Orange Juice is Pi’s mother, and Richard Parker is Pi himself. Pi asks the officials which story they prefer, and they say the one with animals. In their final report they commend Pi for surviving at sea with a tiger.