The narrator defends the story he is about to tell, which is framed as a dream. He explains that he fell asleep in the wilderness and dreamed of a man named Christian, who was tormented by spiritual anguish. A spiritual guide named Evangelist visits Christian and urges him to leave the City of Destruction. Evangelist claims that salvation can only be found in the Celestial City, known as Mount Zion.
Christian begs his family to accompany him, unsuccessfully. On his way, Christian falls into a bog called the Slough of Despond, but he is saved. He meets Worldly Wiseman, who urges him to lead a practical, happy existence without religion. Refusing, Christian is sheltered in Goodwill’s house. Goodwill tells Christian to stop by the Interpreter’s home, where Christian learns many lessons about faith.
Walking along the wall of Salvation, Christian sees Christ’s tomb and cross. At this vision, his burden falls to the ground. One of the three Shining Ones, celestial creatures, hands him a rolled certificate for entry to the Celestial City. Christian falls asleep and loses his certificate. Since the certificate is his ticket into the Celestial City, Christian reproaches himself for losing it. After retracing his tracks, he eventually finds the certificate. Walking on, Christian meets the four mistresses of the Palace Beautiful, who provide him shelter. They also feed him and arm him. After descending the Valley of Humiliation, Christian meets the monster Apollyon, who tries to kill him. Christian is armed, and he strikes Apollyon with a sword and then proceeds through the desert-like Valley of the Shadow of Death toward the Celestial City.
Christian meets Faithful, a traveler from his hometown. Faithful and Christian are joined by a third pilgrim, Talkative, whom Christian spurns. Evangelist arrives and warns Faithful and Christian about the wicked town of Vanity, which they will soon enter. Evangelist foretells that either Christian or Faithful will die in Vanity.
The two enter Vanity and visit its famous fair. They resist temptation and are mocked by the townspeople. Eventually the citizens of Vanity imprison Christian and Faithful for mocking their local religion. Faithful defends himself at his trial and is executed, rising to heaven after death. Christian is remanded to prison but later escapes and continues his journey.
Another fellow pilgrim named Hopeful befriends Christian on his way. On their journey, a pilgrim who uses religion as a means to get ahead in the world, named By-ends, crosses their path. Christian rejects his company. The two enter the plain of Ease, where a smooth talker named Demas tempts them with silver. Christian and Hopeful pass him by.
Taking shelter for the night on the grounds of Doubting Castle, they awake to the threats of the castle’s owner, the Giant Despair, who, with the encouragement of his wife, imprisons and tortures them. Christian and Hopeful escape when they remember they possess the key of Promise, which unlocks any door in Despair’s domain.
Proceeding onward, Christian and Hopeful approach the Delectable Mountains near the Celestial City. They encounter wise shepherds who warn them of the treacherous mountains Error and Caution, where previous pilgrims have died. The shepherds point out travelers who wander among tombs nearby, having been blinded by the Giant Despair. They warn the travelers to beware of shortcuts, which may be paths to hell.
The two pilgrims meet Ignorance, a sprightly teenager who believes that living a good life is sufficient to prove one’s religious faith. Christian refutes him, and Ignorance decides to avoid their company. The travelers also meet Flatterer, who snares them in a net, and Atheist, who denies that the Celestial City exists. Crossing the sleep-inducing Enchanted Ground, they try to stay awake by discussing Hopeful’s sinful past and religious doctrine.
Christian and Hopeful gleefully approach the land of Beulah, where the Celestial City is located. The landscape teems with flowers and fruit, and the travelers are refreshed. To reach the gate into the city, they must first cross a river without a bridge. Christian nearly drowns, but Hopeful reminds him of Christ’s love, and Christian emerges safely from the water. The residents of the Celestial City joyously welcome the two pilgrims. In his conclusion to Part I, the narrator expresses hope that his dream be interpreted properly.
In the Introduction to Part II, Bunyan addresses the book as “Christiana,” which is the name of Christian’s wife. This part of The Pilgrim’s Progress tells the story of Christiana and her children’s journey to the Celestial City. The narrator recounts having met an old man, Sagacity, who tells the beginning of Christiana’s story. She decides to pack up and follow Christian to the Celestial City, taking her four sons and a fellow townswoman named Mercy along as a servant. On the way, they cross the Slough of Despond but are blocked at the gate by an angry dog. The gatekeeper lets them through. Continuing on, the sons steal fruit from the devil’s garden, and two ruffians threaten to rape the women, but they escape.
The pilgrims are lodged in the Interpreter’s house. The Interpreter orders his manservant Great-heart to accompany them to the House Beautiful. Mr. Brisk pays court to Mercy but soon stops courting her because of her involvement in charity work. As a result of eating the devil’s fruit, Matthew falls ill but is cured by Dr. Skill. The pilgrims descend into the Valley of Humiliation and cross the Valley of the Shadow of Death. They encounter the giant Maul and slay him. After meeting the old pilgrim Honest, they take shelter with Gaius. The pilgrims continue on their journey and kill the Giant Good-slay then rescue the pilgrims Feeble-mind and Ready-to-Halt. They lodge with Mnason. Crossing the river of life, they kill the Giant Despair and greet the kind shepherds who welcome them into the Delectable Mountains.
Christiana meets the great fighter Valiant-for-truth, who accompanies them. They cross the Enchanted Ground and meet the pilgrim Standfast, who has just spurned Madam Bubble, a beautiful temptress. The pilgrims are welcomed in the Celestial City. Christiana goes to meet her maker, the Master. The other pilgrims soon follow.