1931. Henri Charriere AKA Papillon is a professional Parisian safecracker. His usual day consists of breaking into mansions, stealing expensive jewelry and delivering it to his boss. In return, he was well paid. One day, after a successful robbery, he meets his boss and gives him the diamonds he has just robbed. The latter inquired if he had kept some of the diamonds for himself, but Papillon declined. The boss then brought up a badly beaten man and explained that anyone who lied to him would suffer the same consequences. Papillon was clearly intimidated by the sight, but he remained calm and walked away with the payment. Soon, he meets his wife; Nenette, and gave her the jewelry he had hidden from his boss. As they walked, a man noticed them, especially the necklace Nenette was holding. That night, the couple discussed their future. Nenette wanted to settle down in the countryside, away from the criminal world, but Papillon figured they wouldn't make enough money there. The next morning, as the two continued their discussion, there was a sudden knock on the door. As soon as Papillon opened it, a group of police officers arrested him. He is charged with murder of the same person his boss had beaten up last night. Papillon tries to explain that he has been with his wife all night, but the police ignored his pleas and took him away. Later, at the police station, Papillon is visited by Nenette, who claims to want to testify. However, he stops her and says it won't help. Papillon knows that no matter what he does, the police won't let him go. So instead, he planned a prison break. Before leaving, Papillon tells his girlfriend to move on with her life, but she refuses. After Nenette leaves, Papillon befriends a fellow inmate named Julot, who reveals that escaping from prison costs a lot of money. He then points to a seemingly innocuous man named Louis Dega and says "he is the solution." Apparently Dega is a millionaire who was arrested for making counterfeit money. Even now he has hidden a lot of money in a place where the sun never shines.During this time, all prisoners are being taken by boat to the penal colony of French Guiana. At night, Papillon approaches Dega and offers to protect him for money, but he refuses. Late at night, while all the prisoners are resting, Dega notices that the guy next to him has been brutally murdered. Turns out he had some money hidden in his stomach, and that's why he became a target. Dega was so frightened by the incident that the next morning he went to Papillon and accepted the offer. The deal was that Dega would be protected until he reaches the penal colony. He doesn't want to run away with Papillon, because he thinks his wife will get him out soon. Then while everyone was resting, the last night's killer targeted Dega. He slowly advanced to punch his victim, but this time Papillon came to the rescue. The two engage in a fight, this warns the officers. Papillon was punished, but he doesn't seem to care. He's just glad Dega wasn't killed. The next morning, the boat finally reached the prison. Before everyone could continue, Juliet purposely injured himself in order to be taken to the infirmary. His plan is to escape from there, as the infirmary is the least protected place. After a while, Papillon and the others finally reach the colony where they will be imprisoned . The place is full of deadly criminals, many of whom have been charged with murder. The prison warden is also an evil man. He gathers all the new prisoners and reveals that escaping from the place is impossible. If someone is caught, they will be held in solitary confinement for 2 years. If they are caught for the second time, quarantine for 3 years. And if caught escaping a third time, they will be sent to the infamous "Demon Island", a place where people go crazy. The director also explained that if someone committed murder, they would be publicly beheaded on the guillotine. In the next scene, all the prisoners are tasked with picking up rocks. While Papillon does this effectively, Dega is struggling to cope up, because he is not used to labor. Later, Papillon meets a boatman and offers him a large amount of cash in exchange for a boat. The man agreed and told Papillon to arrive at the shore the next night. Soon after, a dangerous-looking prisoner discovers the plan and approaches Dega to take his money. But even now, Papillon has come to the rescue. He fights the man and defeats him, though he is wounded in the process. Seeing this, Dega realized that he wouldn't be able to survive even a day without Papillon. By the time his wife finds a way to get him out, he will be long dead. So with no other choice, Dega also joins Papillon in his escape plan. The next morning, all the prisoners were summoned to the yard to witness an execution. It turns out that while trying to escape, Julot killed two guards. He will be punished with a guillotine. As all the prisoners watched in horror, Julot is fitted to the device and decapitated. The warden then orders Papillon and Dega to bring the corpse to the burial site. Unfortunately, on the way, Dega broke down. He had never even seen a dead body in his life, but now they made him carry a headless man. Papillon encouraged him to get up, but to no avail. Soon after, the guards also came and threatened Dega to pick up the body. When he refused, one of them began to whip him in the back. Papillon couldn't take it anymore, so in a fit of rage, he picked up a rock and hit the guard on the head. Then he ran away, but poor Dega couldn't move even an inch out of fear. At night, Papillon came to the shore and met the boatman. He asked for the boat, but to his surprise the man started laughing. When Papillon turned around, he noticed some guards. It turned out that the boatman had foretold the prison warden of the escape. He receives a decent amount of money every time he provides information about a prisoner trying to escape. Soon after, Papillon is taken back to prison, and the director gives him the good news. The guard he punched earlier is still alive, which means Papillon won't be sentenced to death. Instead, he will be held in solitary confinement on another island. When he arrived, he found the place deserted and dark. There is only one rule; don't make noise. In the old prison, inmates could walk around and chat with their friends, but in this prison, they were kept in a small room. Even talking to yourself is a punishable offense here. Also, the food was not enough and very bad. Papillon received only one meal, which was a strange soup. But one day, all of a sudden, he received a coconut. Inside there is a note mentioning that he will now get coconuts every day. Realizing it was Dega's, Papillon happily ate the meal. This lasted for several weeks, but the warden eventually discovered and killed the guard serving the food. He then confronts Papillon and asks who is responsible. As expected, the latter part reveals nothing. As a punishment, the warden halved his already inadequate ration. A month has passed; Papillon has become very weak due to lack of nutrients in his body. The warden approached him again with a delicious meal in hand and asked who sent him the coconut. But as before, Papillon remained silent. Enraged, the warden decided to leave him in the dark for the rest of the sentence. Now Papillon is left in a terrifying situation; He didn't have enough food, he didn't have anyone to talk to, and he couldn't even see his surroundings. Gradually, the quietness and lack of suitable food began to drive him crazy. Papillon became so weak that he couldn't move, so he was taken to the prison hospital. Coincidentally, Dega started working at the same place. Over the past year and a half, he has earned the trust of the director, giving him extra protection and privileges. One day, Dega meets his friend and learns that he is only pretending to be crazy. Papillon knew it was the only way back to prison, so he started acting like a maniac. The duo then began to discuss their escape plan again. This time, they chose two other prisoners as effective assistants. Papillon wants someone strong and cunning, while Dega wants to help someone who is constantly being taken advantage of. In the end, they recruit a bully named Celier and a guy who gets bullied all the time; Mature. Dega then gives all of his savings to Celier, who uses his connections to buy a boat. The next night, a movie will be shown, and that's when the quartet plans to escape. Dega was worried about the whole thing, and at one point even considered backing out. However, Papillon, making him understand that it was their only chance of freedom. Now or never. In the next scene, we are taken to the movie night show. Several officials arrived and Dega served them drinks. According to the plan, he drugged them and waited for the perfect moment to steal the key to the main gate. Inside, Papillon and the others were waiting for Dega to return when suddenly it started to rain. This causes a power outage. Frightened, Celier suggested they run away and find another route, but Papillon refused. He won't leave without his friend. Luckily, Dega arrived just in time with the key. Taking advantage of the dark, the group broke open the main door and quickly escaped from the prison. After a while, they came to an impasse; The only way to get to the shore is to jump. Papillon, Celier and Maturrete successfully land, but when it's Dega's turn, the lights suddenly come back on. This startled him, causing him to land awkwardly and break his leg. Now that he can't walk, Celier offers them to let him stay, but Papillon again refuses. He, along with Maturette carry the wounded Dega and eventually reach the shore, where a boat is waiting for them. Without wasting time, the four jumped on board and sailed into the darkness of the ocean. The next morning, hours had passed since their escape, but Celier notes that they still haven't reached very far. This is because the boat is very small and cannot support the weight of four people. At that time, they saw a storm approaching them. Realizing they have very little time, Celier throws Maturette into the sea, then goes after Dega. However, Papillon got in the way, leading to a brutal fight. Celier, being the taller man, got the upper hand and was about to kill Papillon when suddenly Dega stabbed him from behind. The duo then threw him off the boat and helped Maturette climb back up. After a while, the great storm engulfed them and the screen turned black. When they wake up, they find themselves on an island. It turned out that a nearby community had seen them floating in the ocean and saved them. As the confused Papillon wanders around, a nun greets him and reveals that they are in Colombia. She also mentioned that she knew what they did and where they came from. Papillon tries to explain himself, but the nun says he is safe, as long as he repents for his sins. That night, Papillon meets his best friend and tells him they must leave immediately. However, Dega refused, saying their deal was over. He was tired of running and now just wanted to stay in one place forever.Therefore, Papillon decided to leave this place alone. But as he approached the boat, he noticed two officers stopping. It turned out that the evil nun had offered her position to the authorities. Alarmed, Papillon quickly returns to Dega and helps him up, but by then the officers had noticed them. Maturette is shot immediately while Papillon and Dega are captured and sent back to prison again. Cut to five years later, Papillon has served his prison term in solitary confinement, and now he's been sent to Devil's Island. To his surprise, he finds Dega there. It was revealed that he received a harsher punishment because he spiked the drinks of the officers. Dega was brought to Devil's Island shortly after returning from Colombia. Both are happy to reunite after 5 long years. They may have aged, but the friendship and bond are still the same. That evening, as Papillon looked out at the sea, an idea popped into his head. He approached Dega and told him that if they could make a small raft, the waves would take them to the nearest shore. However, this time, Dega refused to participate. He explained that for the past 5 years, he has lived a peaceful life, without any disturbance or violence. He also learns that his wife is already married to someone else, so there is no need to go back. However, he decided to help Papillon make the coconut raft. The next morning, the two friends hugged and said goodbye. Papillon then threw the raft into the sea before jumping on himself. The plan is working and the waves seem to be taking him somewhere. As he walked away, Dega was in tears. In the final scene, we are transported to the year 1967. Papillon currently lives in Venezuela, as he is still a wanted criminal in France. But in 1969, he was pardoned for all his crimes. Papillon wrote a memoir of all the events, which he now plans to publish. The film ends when he arrives in Paris for the first time in 38 long years.