Piscine Molitor Patel, nicknamed as Pi because people find his name a bit lengthy and tough to pronounce, lives in Pondicherry with his family, who own a zoo. It is around 1970’s when the political situation of Pondicherry begins changing. Thus, his father comes out with an option of migrating to Canada and selling some of their animals in the North America. But at the same time, Pi is caught by the quest of religions, spirituality, and God. While speeding up his efforts, he seeks chances to meet people from different religions, and in a hope of finding a resolute answer he starts following religions like Christianity, Hinduism and Islam.
The family boards the Japanese cargo ship with some of the animals. Midway their voyage, the ship falls in the grip of storm, Pi is little excited to see the storm, and hence he comes out at the dock of the ship. Next, he is thrown onto a lifeboat. The ship sinks down with no survivor except Pi – and to accompany him on the lifeboat are a hyena, an injured zebra, an innocent orangutan, and Richard Parker, a Bengal tiger.
And soon the fight for survival begins, as an upshot the hyena kills and eats both: the zebra and the orangutan. After sometime, Richard Parker, who was hidden under a tarpaulin cover, comes out only to finish the hyena. Seeing the bloodshed, Pi fears and soon makes a raft with the help of oars and lifejackets so as to keep himself alive and at a safe distance from the tiger. They are somewhere in the middle of the Pacific Ocean, helpless but struggling for life. Pi using his wits, collects ration and drinkable water and a manual which instructs how to survive as a lost person in the vastness of the ocean.
Pi maintains safe distance from the tiger but at the same time controls and keeps him alive by hunting fish and getting water from the rain and the distillery. He controls Richard Parker by blowing various-toned whistle gestures and rocking the boat which causes seasickness to the tiger. A mutual understanding settles between them but Pi can never testify it. They also arrive at a floating island, made of algae, full of meerkats. Here they get fresh water and fish without efforts but soon Pi discovers that the island is carnivorous, hence they both abandon it. And again head for nowhere.
After an ordeal of 227 days, the lifeboat washes onto a beach in Mexico; Richard Parker disappears in the nearby jungle, while Pi weeps at both: he finds land but Richard Parker departs abruptly. He is of course heartbroken.
In the hospital, Pi is seen by two Japanese officials who refuse to believe his original story. To keep their hearts happy, he fabricates another story in which there is no animal involved. However, Japanese officials draw a parallel between the two stories and leave him by taking his first story.