The eponymous main character is an eighteen-year-old living in a town called Hull in England in the seventeenth century. He is the youngest of three brothers, and he wants to travel the seas instead of becoming a lawyer like his father hopes he will. Robinson’s family does not support his wishes and his father tries to tell him that it would make for a much nicer and more stable life if he were to pursue a career being a lawyer. This could be because both his older brothers have disappeared for their thirst for adventure, one died in the war and the other simply vanished one day. Robinson is set to inherit his father’s title and it would be better for him to be a lawyer as the heir.
At first, Robinson is all set to follow what his father says, but soon he loses his way and gives in to his want for adventure. He runs away from his duties with a friend on a ship set for London, and his troubles begin almost as soon as he does. The first unlucky event that comes his way is a storm that almost kills him and his friend. Their ship stops at Yarmouth, which is where Robinson’s friend finds out about how he ran away and no one actually knows where he is now. This angers him and they have a falling out. They go their separate ways, with Robinson now trying to find a way to London by land. He considers returning to Hull for a moment but decides he can’t face the humiliation. He gets on a ship as a merchant and it actually proves a successful journey for him financially. This makes him plan for another right after, but he leaves the money he has made behind with a widow he has befriended. This second trip is not like the first. He boards a ship set for Guiana, but they are attacked mid-journey by Turkish pirates. The people on board are taken to a town in North Africa called Sallee and made to be slaves. Robinson plots his escape for two years before he finally gets a chance to do it. He and two Moorish boys are sent out fishing. He tosses one of the boys off the ship and he says to Xury, the other one, that he won’t throw him off too as long as he is loyal to him. They come across a Portuguese ship on their travels and the captain allows them aboard for free. He also buys Xury from Robinson and takes them to Brazil. Once there, Robinson sees the money that plantations bring and he buys one himself, which brings him much success. He is approached by some men to begin a slave trading business which would be very lucrative. Robinson sets off to bring back slaves from West Africa but he ends up being shipwrecked on an island.
He realizes he is the only one onboard who survived the shipwreck and tries to figure out how to get food and shelter alone. He loots the ship over 12 visits for all that’s left there, ammunition, gunpowder, any food left and whatever else he could find that seemed of value. On the island, he raises goats for food and makes a shelter for himself. On a cross, he keeps track of how long he has been on the island by making a notch for every day he has been there. He has a journal which he writes in about his attempts at making a home for himself on the island. This includes events like trying to make candles, finding grain that he can now cultivate, and building a cellar, amongst other things. About nine months after he has been shipwrecked, he gets very sick and starts to hallucinate of an angel who is visiting him and telling him he should repent before it’s too late. While drunk on rum that has been steeped in tobacco, he has a religious experience that leaves him believing that God has forgiven him all his past sins. Once he starts to feel better, he begins exploring the area and finally realizes it’s an island that he’s on. He discovers a valley full of grapes he can rest in the shade in. Slowly, Robinson starts to feel better about his solitude on the island. He even starts to call himself its king. He keeps a pet parrot and also a goat. He builds a small boat and tries to explore the island with it, but almost dies. When he reaches the shore his pet parrot calls his name, and he is grateful he’s okay once more. Many more years are spent like this.
This is until Robinson finds the footprint of a man on the shore. At first, he believes it’s the devil, but then he figures it must be a cannibal he has heard lives nearby. Scared for his life, he is always on edge about them finding him. He ends up taking extreme measures for his safety, he takes his goats underground at night into his cellar and even figures out how to cook there. Another shipwreck comes to shore one day but the ship is empty by the time he gets to it. He thinks he is safe but soon begins finding human remains on shore; the cannibals have had a feast. Once again, he is afraid for his life. He comes across thirty cannibals on their way to the shore. Their prisoner escapes from their grasp and comes toward Robinson, who saves his life by killing the cannibals with his guns or scaring them away. The savage says he will dedicate his life to Robinson for freeing him. He is named Friday because of the day he broke free and he becomes Robinson’s servant.
Robinson comes to see Friday as an uplifting and bright fellow; he takes on some English words and basic concepts of Christianity from him. In return, from Friday Robinson learns about how the cannibals who held him prisoner are one faction of many and they would never eat one of their own, only their enemies. Robinson also finds out from Friday that the shipwrecked people from the ship on shore are still alive, they were rescued by the cannibals. They are Spaniards who are living close by. Friday is wanting to go back home to his family and Robinson is sad at the thought of losing his only friend. He then ponders on going to join the Spaniards but Friday says he wants to die instead of losing Robinson. They build a boat together to go to where the cannibals live. They are shocked when 21 cannibals show up at their doorstep first. They come with three prisoners, and together Friday and Robinson defeat the cannibals. One of the prisoners is a Spaniard, whom they let go and one turns out to be Friday’s father. They go back to where Robinson lives and take shelter and sustenance. Robinson makes preparations for the four of them to live together from then on. Robinson and Friday stay behind and the other two get on a canoe to see more of the land nearby.
About a week later the pair notices an English ship coming to the island, which Robinson is wary of. 11 men approach the island, along with 3 prisoners on a boat. Two are left behind to watch the captives while nine go off to see the island. Friday and Robinson defeat the guards and set the prisoners free. One of them turns out to be the captain of the ship, taken prisoner after a mutiny. Robinson agrees to help the captain if he agrees to leave the island undisturbed and he also takes both of them back to England. To confuse and make them dizzy, Robinson and Friday shout to the rest of the crew from different places, and they run around and get tired. After this they approach the mutineers, offering the rest of the group freedom if they give up their leader’s life. The group agrees to this. The captain and Robinson act like the island is actually imperial land and that the crew is being sent to England to face their sentencing. They keep five of the men onshore while the rest are commanded to bring the ship. Once it’s done, Robinson almost collapses.
Over 27 years after he’s been shipwrecked, Robinson finally gets on a ship back to England. His family is dead besides his two sisters. The widow he left his money with has kept it safe all these years. He finds out his plantations in Brazil have done really well and are worth a lot of money. After selling his plantations he now has a large sum of money at his disposal. He gives some to the widow and some to his sisters. He settles down in the English countryside with his wife and three kids. When his wife passes, he goes out to sea once more.