The Silver Chair Begins with the introduction of Jill Pole who is sitting behind the gymnasium at her school, Experiment House, crying. The bullies at school have been bothering her and her only refuge from their abuse was there. She is interrupted in her cry by a young boy who tells her to dry up about the whole issue. Jill flies into a rage and accuses the boy of being one of "them" because of the way he behaved last term. He defends himself, saying that this term he has done nothing of the sort, that some interesting things happened to him over the holidays. Jill admits that he has changed some and asks what happened. The boy, Eustace, tells her that he has been out of this world and that the Pevensies had been there too. She asks if they could get there now. Eustace tells her that the only way to get there is by magic. They eventually stand and say Aslan's name three times each. They are interrupted by one of "them" who is looking for Jill. Jill and Eustace run up the hill to get away from the others.

When they get to the top, they are trapped by wall with a door. One time before, that door was left open but has not been open since. Eustace decides to try it anyway and to his surprise, the door opens. The two do not immediately enter the opening for, instead of the dull gray autumn skies of England, the are looking at bright blue summer skies. Nevertheless, the sound of their pursuers helps them enter the door and close it behind them.

They find themselves standing in what appears to be a thin woods with birds fluttering about. Eustace suddenly jerks Jill back as they are standing on the edge of a very high cliff. Jill yanks her arm away from him and steps closer to the edge of the cliff. The dizzying height scares her but she is reluctant to step back for fear of what Eustace would say. Deciding she doesn't care what he says, she opts to move away from the ledge but is unable to move. Eustace reaches for her and in her attempt to get away from him, she knocks him over the cliff. As suddenly as the scream of Eustace comes, a Lion appears out of nowhere and blows over the edge of the cliff. Jill watches as Eustace floats away from her into the blue expanse below. The Lion walks slowly away and Jill, who has fallen to her stomach, is reluctant to move.

When she does finally get up, she does not see the Lion but feels she must move on because of her incredible thirst. She can hear the sound of rushing water and moves toward the sound. When she finally does see the stream, she wants to drink but halts. The Lion is between her and the stream. The Lion invites her to drink. She asks Him to leave, but His countenance gives her His answer. She asks if He would promise not to harm her. He makes no promise. She wants to know if He eats girls and the Lion tells her that He has eaten boys, girls, men, women, and societies. She is desperate with thirst so she decides anyway to drink, regardless of the consequences.

After she has been refreshed, Aslan, the Lion, calls her to him and questions her about Eustace's fall and commands that she not show off any more. He then gives her a task, commanding that she go to Narnia to seek out the Prince, who has been missing for 10 years. He gives her four signs that she must follow in order to best find the Prince. First, when Eustace arrives in Narnia, he will see an old friend and he must go and speak to that friend at once in order to have good help. Second, they must go to the north of Narnia to find a giant city. Third, there will be instructions written on a stone in that city and they must follow those instructions. Fourth, they will know the Prince because he will be the first person they will meet who will ask them to do something in the Name of Aslan. He takes Jill back to the cliff, making her repeat the signs over and over until she gets them right. He gives her final instructions and blows her to Narnia. After several hours in the air, she lands on the eastern edge of Narnia next to Eustace who is watching a royal procession toward a magnificent ship.

Jill implores Eustace to look for anyone he knows. He is more interested in what is happening than her request so they continue to watch until the ship is pulled away from the wharf. He is about to ask Jill what her situation is when they are interrupted by an owl who suddenly descends upon them. The owl, Glimfeather, asks who they are and why they have come. Jill tells him that they are to rescue Prince Rilian. Glimfeather tells them that the King, who should have known of this matter, has just taken ship. Eustace asks what the King's name is and is disturbed to learn that it is Caspian X. Glimfeather takes them to the Lord Regent, Trumpkin the Dwarf (see Prince Caspian). Trumpkin is an aged dwarf by now and has some trouble hearing Glimfeather but is finally convinced of who the two children are and will meet with them the following day to discuss their business.

During the night, Glimfeather comes to Jill's room and asks her if she is serious about saving Rilian. She answers affirmatively. Glimfeather says he will help them but she must get dressed for travel. Glimfeather leaves her to get Eustace. Changed into her English clothes, she rides Glimfeather to an old tower away from the castle where they are to meet with a parliament of owls.

Before the parliament is to begin, Eustace proclaims loyalty to Caspian and will have nothing to do with a plot against him. The owls are also loyal to Caspian. The reason the parliament must be held in secret is because Trumpkin will follow a law which states that none are to go in search of Rilian since so many have been lost in the attempt before. The children learn Rilian's story. Ten years ago, the prince and his mother went maying with several of their court. During a brief rest, the queen was bitten by a green snake and died. The prince rode out in search of the snake to avenge his mother but to no avail. Drinian asked the prince why he continued to ride in search of the snake but Rilian tells him that he has given up the search for the snake but goes there for another, more beautiful purpose. Curious, Drinian rides with Rilian the following day and sees a woman dressed in a green dress, the object of Rilian's affections. The following day, the prince again rode out to meet the woman and was never seen again.

It is decided that the children will be taken to the marsh-wiggles since they know the northern terrain better than anyone. After a brief flight, the children are taken in by Puddleglum and they rest for the night in his wig-wam. The following morning, the children awake and speak to Puddleglum as he fishes for eels. They find that he is rather a pessimist who is usually wrong about the situations he predicts. They build a fire on which to cook lunch and discuss their plans over eel stew. They shall need to go through Ettinsmoor and north to reach the ruined city of the giants. Preparations are made to leave the following day.

The children travel through Ettinsmoor, where they encounter a group of about 50 giants who appear to be throwing stones at them but are in fact playing a game. The giants fairly well ignore the travelers. The journey through Ettinsmoor is long, cold, and rough. At the north of Ettinsmoor, they cross a giant bridge while Jill assumes is a sign that is leading them toward the ruined city of the giants. Across the bridge, they meet a young lady and a knight dressed in black armor with visor down. The lady asks where they are going, but Puddleglum refuses to tell their business. The lady directs them toward Harfang, the city of the gentle giants. There they will find lodging, food, and warmth. They must simply tell the giants that the Lady of the Green Kirtle salutes them and sends these two southern children for the Autumn Feast. The idea of sleeping in a bed and taking a hot bath excites the children though Puddleglum is less than exuberant, pointing out that Aslan said nothing about sleeping in the house of giants. They resume their journey down the road toward Harfang. The lady's words affect the children greatly. Jill forgets the signs and fails to repeat them. All they could think of was hot baths and beds. After several days, they arrive at Harfang.

Once the children spot Harfang, the journey becomes harder. Driving snow and wind blinds them and they must stumble up giant steps and across open stone terraces. In their blindness, Jill slips into a trench. They investigate the trench and find that it leads to dead ends. Puddleglum pulls the children from the trench and they approach the gate at Harfang. A giant porter opens the gate and, after hearing that the Lady of the Green Kirtle had sent them to the city, allows the travelers to enter. They are warmed by the fire and Puddleglum is given something to drink which causes him to become drunk. The children are taken to the throne room where they meet the king and queen. The royal couple greets them, delighted at having them for the Autumn Feast. They order the children and Puddleglum taken away and given food, toys, and beds.

In her sleep, Jill dreams that Aslan comes to her and asks her to repeat the signs. She is unable to remember them. He takes her to the window of her room, where she can look out. There she sees the words "UNDER ME". When she wakes she does not remember the dream. In the morning, Eustace and Puddleglum are brought to her room. Eustace notices the window seat and crawls up to have a look out. Outside they see the remains of a giant city with words carved into the stone, "UNDER ME". Jill remembers the dream, dismayed that she did not see it the night before. It is Eustace who points out that they did see the words. Jill had fallen into the "E" in "ME". They decide that they must get out of the castle. They decide that they will pretend to enjoy being there, longing for the feast. By doing so, no one would suspect that they are trying to get away.

Jill's nurse opens the door to her room and invites them to see the royal hunting party as it leaves. The children bolt out of the room and find the hunting party about to set off. Jill runs up to the queen and asks if they may run over the castle, telling her how they long for the feast to come. The queen gives her permission to the children to look around the castle and laughs at Jill's excitement about the feast. Jill spends the better part of the day loving up to the housemaids and other giants who shed tears at the innocence of the children.

At lunch, the children learned something else which made them want to leave the city of the gentle giants more quickly. While eating venison, Puddleglum tells them to stop. The stag they are eating was a talking stag. The children decide that they have had enough of lunch and resume their explorations of the house. They go to the kitchen where they chat with the cook. They learn that the door to the scullery is open. While waiting for the cook to fall asleep, Jill reads a cookbook which lies open on the table. The first entry she reads is 'Mallard'. The next alphabetical entry is 'Man'. The book refers to man as a delicacy and an integral part of the Autumn feast. She shows the book to the others who read the next entry, 'Marsh-wiggle'. There is no doubt now that the children must leave at once and the giant cook obliges them by falling fast asleep. The three slip out the scullery door and cross the plain towards the giant city.

They do not get far before they hear a horn, the returning hunting party. The party spots them and gives chase. They run toward the ruined city. At the base of the giant steps, Puddleglum spots a hole which goes under the stairs. He crawls through the hole, followed by Eustace, and finally Jill. They fill the entryway with rocks to keep the pursuing dogs out and begin to move away from the opening. The space is completely dark and they must feel their way around. They do not go far before the floor slopes sharply downward and they slide for what seems like an eternity before they reach the bottom. They cannot see anything in the total blackness. They call out to one another, assured that all are not injured. Unsure of what to do, they simply sit and do nothing. A sudden voice breaks the silence, asking what their business is in the Deep Realm.

The voice tells them that he is the Warden of the Marches of the Underland and with him are a hundred armed earthmen. They are to go to the queen of the Underland who will deal with them. A lamp is lit and the children see the creatures who appear to be very sad gnomes. The travelers get up and are forced to follow the creatures through the caves. They pass through several caverns, on of which has a number of odd animals which appear to be sleeping and will not wake until the world's end. The pass through a cavern in which sleeps a huge man. They learn that this is Father Time who will not wake until the world's end. Finally, after several caverns and a completely downward journey, the group arrives at the shores of an underwater sea where they take to a ship and set sail. They are on board for what appears to be several days before they see signs of civilization. They land and in the city before them they see thousands of earthmen all bustling about looking very miserable and busy indeed. The Warden takes them to the castle but the Queen is away. The children are about to be put into prison but a voice instructs the Warden to bring the Overworlders to him. Reluctantly, the warden complies.

The children are brought to the young man who greets them and tells them that he recognizes them from the road to Harfang. He was the silent black knight. Eustace tells him that it was rather unkind for the lady to send them to a city where they were to be dinner. The knight tells them that the lady meant well and asks them their business in the Underworld. Jill tells him that they are looking for Rilian of Narnia, a name the knight does not recognize. She tells him that they saw a writing on the stones of the giant city. The knight laughs and says that the writing is part of a larger, now destroyed script. They were deceived. The knight tells them that he is man under "strange afflictions" and it is the Queen who keeps him from harm. She has promised the knight a kingdom in Overland and her hand in marriage.

The prince tells them the full story over dinner. He does not know how he came into the Underland but he is bound by a spell. Every night he must be strapped down while the fit is upon him for if he were free he would kill all he saw and then turn in to a horrible serpent. The lady is preparing to take a kingdom in Overland for once the knight is a king, he shall be free from his enchantment. The earthmen are even now digging a tunnel which leads to Overland and when it is finished he will storm out with hundreds of Earthmen with him to overthrow the kingdom they find there and assume the throne himself. Jill and Eustace are appalled by the knight's behavior. However, the knight tells them that the hour of his nightly fit is upon him. They will not be allowed to stay with him during the fit, but they can leave and come back after he has been tied down. They are shown a door which leads them to the knight's apartments where they can wash themselves. They return to the knight a short time later. He has been strapped to a silver chair. The knight tells them that whatever they do, they are not to free him from his bonds or he will surely kill them all. The knight groans and babbles before coming to himself.

He implores the children to free him. He tells them that it is in this hour that he is in his right mind, that all the rest of the day he is enchanted. The children do not release him. The knight begs and screams for them to cut his bonds, imploring them by all that is important, even by Aslan himself. The children jump in surprise at Aslan's name - it is the fourth sign. After a few moments of debate, the bonds are cut and the knight is free. He bounds across the room and unsheathes his sword, taking it to and destroying the silver chair. He then turns to face the others. The knight is astounded to see a true Narnian marsh-wiggle. He identifies himself as Rilian of Narnia, only son of Caspian the Navigator. The children tell him that Caspian is very old and has taken to the sea in search of Aslan. Rilian learns that he has been a captive for ten years. As they are talking, they hear footsteps at the door. Rilian opens the door and, to everyone's amazement, the Queen of Underworld enters.

She takes immediate appraisal of the situation and asks why the prince is not bound and whether the children have destroyed the chair, his only refuge. the prince curtly tells her that he is free from his enchantment and that he refuses to rush upon the people of Overworld and take their kingdom as his own. He identifies himself to her as Rilian, Prince of Narnia and requests a guide to lead them out of Underworld. As he talks, the queen very slowly works her way toward the fire and there throws a green powder into the fire. A thick smoke begins to fill the room as the queen plays a mandolin-like instrument. She talks to the others, asking them about Narnia. They try to tell her but the enchantment is beginning to take hold of them. She tells them that there is no Overland, no world but her own. they try to argue but the smell and the music are too much. Jill is finally able to say Aslan's name, which disturbs the queen slightly but she rebukes the concept of Aslan as a child's tale and shames the children for playing such games. Puddleglum musters the strength to approach the fire and stamps it out, burning his foot but destroying the queen's magic at the same time. The queen is outraged and begins transforming herself into the form of a large green serpent. She coils herself around Rilian but is quickly destroyed by combined attacks from Eustace, Puddleglum, and Rilian himself. With the witch dead, Rilian declares that his royal mother is avenged and that they should rest before moving on. While resting, they attend to Puddleglum's burnt foot.

While discussing their plans for escaping from Underworld, they hear a lot of noise, which is unusual in the normal quiet of the land. They look out the window and see hundreds of Earthmen sneaking about and hiding in the shadows cast from a mysterious red glow. The gnomes appear to be readying themselves for battle. Finally, they see that the water from the sea is washing over the streets of Underland. Rilian tells them that they can take horses and ride to the diggings which were leading to Overland. They do so and ride out among the Earthmen. They ride toward the unidentified red glow but are afraid that the Earthmen will attack. They decide to capture one and learn from it what the gnome's plans are. Puddleglum slips from his horse and hides, grabbing the first Earthman that passes. The gnome promises to talk as long as they will not tell the queen that he said anything. Once Rilian tells the gnome that the queen is dead, the gnome greets him as a friend.

The gnome is named Golg. He tells Rilian that he and the other Earthmen were going about their normal business when they suddenly realized that they did not want to do this work and dropped what they were doing. Once they realized that they had been enchanted and were now free, they began to move toward the red glow in hopes of leaving Underworld. The glow comes from a split in the ground which leads to the Really Deep Land, the land of Bism. The four remount their horses and follow Golg to the chasm, where he will return to Bism after showing them the way to Overland. Golg invites the Narnians to join him or at least visit in Bism. Rilian is tempted to go but decides that he must return to Narnia. Golg points the way to the digging toward Overworld just as a voice declares that the chasm closes. Golg bids farewell as he dives into the crack.

Once the chasm closes, the children make their way down the road, which is beginning to flood. The water is shallow enough to ford and it ascends from that time on, away from the rising flood. They travel for some hours before the lamps lighting the way begin to go out. Just as the ceiling get too low to proceed by horseback, the final two lights go out and they are left in total darkness. After walking some in the dark, Eustace sees a patch of light ahead. Just as he notices the light, Puddleglum comes to a dead end. The light is pale and blue, not sunlight as they had hoped. Jill climbs onto Puddleglum's shoulders to look out. She can see some but wants to stand on Puddleglum's shoulders to get a clear look around her. Before she says much, her voice is muffled and, after sputtering some, Jill calls out to someone then is pulled from Puddleglum's shoulders, disappearing into the hole.

What Jill saw was a hillside sloping downward before her. At the bottom were a group of fauns and dryads dancing. Dwarfs circled around the dancers, throwing snowballs through the dance. It was one of these that caused Jill to be cut off so quickly - it hit her squarely in the mouth. Once able to talk, she calls out to the group who pulls her from the hole and, on her instructions, begin digging the others out.

Meanwhile, Eustace with sword drawn, crawls up on Puddleglum's shoulders to see what happened to Jill. As he emerges, he gets snow in his face. In his confusion, he sees several creatures running toward him to pull him out and, unable to determine whether they are friend or enemy, begins slashing at them with his sword. Jill tells him to stop, that they are in Narnia and the dwarfs who are pulling him free are friends. the dwarfs and several moles tear away at the hill, opening a hole through which Puddleglum, Rilian, and the horses emerge. Puddleglum is welcomed and told that his fame has spread across Narnia. At the sight of Rilian, hats are removed and knees are bent. They go to a nearby cave where a fire is lit and table set and all listen as Rilian tells of his adventures. Jill and Eustace, however, fall fast asleep.

When Jill awakes next morning, she tries to wake Eustace and Puddleglum. In doing so, she disturbs someone overhead - Glimfeather the owl. He has come to tell her that Rilian has left and that she and Eustace are to go after him. Jill and Eustace are offered the rare privilege to ride a centaur. After breakfast and farewells to Puddleglum, the two ride out to the wharf where Caspian's ship is returning to port. Caspian had seen Aslan before sailing far and was told that his son would be waiting for him when he got back to Narnia. When the ship is moored, a Lord disembarks and approaches Rilian and Trumpkin. The three talk for a moment before four others are seen carrying the king on his bed from the ship. They set the king before Rilian, who kneels beside his father, receives his blessing, and weeps as his father dies.

The children slip off the centaurs' backs as mournful music plays. A voices calls out behind the children and they turn to see Aslan there. Jill is ashamed because she behaved so poorly during the entire adventure. Aslan consoles her and tells them that they are going home. Aslan blows and the whole of Narnia fades around them and they find themselves once again on the Mountain of Aslan. Aslan leads them to a stream in which the dead Caspian lies. the Lion tells Eustace to retrieve a thorn from a thicket and pierce His paw. Reluctantly, Eustace does as he is told and a great drop of blood falls into the water over Caspian. The gray beard turns yellow, then gets shorter and finally disappears all together. A fresh, young Caspian jumps from the water and hugs Aslan. He turns to greet Eustace who is reluctant to shake hands with a ghost. All is explained, Caspian is not a ghost. Caspian asks if he may see Jill's world and Aslan allows him to go for five minutes. After some explanation of the kinds of people the children know at Experiment House, Caspian enters England with them through the same door and a gaping hole which Aslan made in the wall. Aslan sits with his back to England as Caspian, Jill and Eustace spank the bullies with swords and riding crops. The Head of Experiment House calls the police and is eventually removed from her position to one in Parliament. Caspian returns to Aslan's Country and the children rush in to change clothes. The bullies were all expelled from Experiment House and the school becomes a much better one. As for the entrance to Underworld, the way is left open and some will enter and sail on the Underland ocean, telling of cities that lay far below. It is suggested that, if the opportunity arises, one should visit those caves.