The narrator dreams he sees a man named Christian who lives in the City of Destruction. He is weighed down by what he reads in a book: that he, his family and neighbors are headed for judgement. This weight takes the literal form of burden on his back, which he can’t remove. Christian tries to explain to his family that their only hope is to leave everything and go to the Celestial City to serve the King, but his wife and children think he’s crazy to want to leave their comfortable life.
A man named Evangelist finds Christian in his distress and explains that there is a path that leads to the Celestial City through a small wicket gate. The way is difficult and dangerous to travel. Evangelist warns that other, apparently safer paths go in the same direction for a time, but this narrow way is the only true path to the Celestial City.
Heartened that someone has recognized his desire for change, Christian takes Evangelist’s advice and runs to the wicket gate. His neighbors in the City of Destruction insult him and call for him to come back him. Two neighbors run to join him, but both quickly turn back at the first onset of difficult traveling.
The Keeper of the wicket gate tells Christian to stop at the home of the Interpreter, who will help explain some things about the way and the Celestial City. Once he makes it there, the Interpreter welcomes Christian into his home. Each room in his home holds a lesson about the life he has chosen, and Christian pays careful attention to them all. He learns about the dangers of legalism, the importance of patience, and that he must stay faithful to the end.
After leaving there, Christian arrives at a hill where stands a cross and a tomb. Once he reaches the foot of the Cross, Christian’s burden falls off his back and rolls into the tomb. Free of this weight, Christian rejoices. Then three angels arrive to give him robes of righteousness, a scroll to encourage him, permission to enter the Celestial City and confirmation that here his sins are indeed forgiven. Leaving that place, Christian passes several other pilgrims who have stopped to sleep along the way, or who think they could get into the Celestial City without a scroll and without entering through the wicket gate.
After climbing the Hill of Difficulty, Christian rests for some time at House Beautiful. The people there live to refresh and to teach pilgrims, and they ask him questions about his journey. Like at the house of the Interpreter, they show him several things that have a deeper meaning. They equip him with armor, knowing there are more dangers ahead of him. As Christian leaves, the porter at the gate mentions another pilgrim had passed by recently, named Faithful.
Christian walks through the Valley of Humiliation, where he encounters the beast Apollyon. The monster is a servant of the world who tries to convince Christian to give up the life of a pilgrim and return home to Destruction. Christian refuses. The two battle. Just when Apollyon is about to win, Christian finds strength in quoting Scripture. Apollyon flees, and Christian continues on to the Valley of the Shadow of Death.
Quagmires, hobgoblins, darkness and false ideas about God fill this Valley, and its exit is littered with the bloodied remains of past pilgrims. Nevertheless, Christian makes it through unharmed because the two trolls who lived at the exit, named Pagan and Pope, no longer have any power to attack passersby. As he leaves the Valley, he sees Faithful ahead of him and calls for him to wait up.
Now travelling companions, Christian and Faithful arrive at the town of Vanity, where vendors at a street fair attempt to sell them all manner of worldly goods. Christian and Faithful refuse, angering the vendors to the point of persecution and arrest on false charges. In the face of mockery, abuse and imprisonment, the two pilgrims endure their trials with patience and humility. Faithful is martyred. Over time, the citizens of Vanity grow ashamed of what they’ve done and allow Christian to go free. A young man named Hopeful, inspired by Faithful’s death, becomes Christian’s new companion. The two ask one another questions about their faith and build each other up as they travel.
Eventually their path becomes even more difficult, and walking is exhausting. They find a fenced-off meadow with a pleasanter, easier path that appears to follow parallel to the way. Although Hopeful hesitates, Christian persuades him that there is no harm in taking the easier path for a little while. Soon, however, the two end up very lost. The Giant Despair finds them, and accusing them of trespassing, takes them captive in his home, Doubting Castle. He starves them and beats them often. The two are trapped in Doubting Castle for some time, until Christian remembers he has a key that will open any lock. So the two escape.
Hopeful and Christian continue along their original path, asking one another and any passing pilgrims questions about their faith, until they finally reach the Celestial City. The two pilgrims must cross a river with no bridge to enter the kingdom. On the opposite shore, they are greeted by angels and trumpets and join in praising the King of the land.
The narrator begins the second part of the story by acknowledging that the reader might be interested in what happened to Christian’s wife. It’s explained that once word came back to Destruction that Christian had made it to the Celestial City, his wife, Christiana, had a change of heart. Fear and guilt consume her at the thought of not only ignoring her husband’s needs, but also at the realization that she kept her four sons from following their father to the way that leads to life.
After several restless nights, an angel appears with a message: Because the King has been so pleased with Christian, she and her children have been invited to join him in the Celestial City. Christiana immediately begins packing for the journey.
As the family prepares to leave, two women stop for a visit. One, Mrs. Timorous, is angered that Christiana would lead her children from the safety of home. The other, Mercy, recognizes that Christiana must truly believe the journey is for the children’s benefit. Mrs. Timorous leaves in a huff to gossip with the other townswomen, but Mercy asks to come along to the wicket gate, offering to help take care of the children.
Christiana accepts. At the wicket gate, Mercy is given permission to continue with Christian’s family, as the King invites all to come to him. The Keeper asks if they will need a guide. Christiana and Mercy decline, thinking that together they will be strong enough to face whatever comes.
Shortly after they leave the gatehouse, the children find some fruit hanging over the wall that divides Beelzebub’s land from the way. Although Christiana tells the children not to eat, some of them do anyway.
Two men approach Christiana and Mercy with violent intentions. They scream for help, and the two men run away. After the encounter, they decide a guide might be helpful, but because they had not asked initially, they will have to wait until they reach the house of the Interpreter to ask again. As on Christian’s journey, the Interpreter shows Mercy, Christiana and her children many strange and interesting sights that teach something about the life of a pilgrim. When they leave, the Interpreter sends his servant Great Heart to be their guide.
Great Heart leads them to the Cross and the tomb. There they discuss the personhood and godhood of Christ and how His righteousness covers our sin. From there they climb the Hill of Difficulty, where Christiana learns a lesson in forgetfulness. Before entering House Beautiful, Great Heart kills the Giant Grim who attempts to block their way, cutting off his head.
The party stays at House Beautiful for a month. Prudence, one of the residents there, quizzes the children on what they believe and why. Mathew, who had eaten the fruit earlier, falls very sick. Dr. Skill arrives with a purge made of natural things to cure him. When that doesn’t work, Skill makes a purge of the body and blood of Christ. After that, Matthew begins to recover.
Great Heart continues to lead Mercy, Christiana and her children along the path, defending them against any danger and pointing out the places where Christian had significant encounters. They pick up several other travelers along the way. When they come across Doubting Castle, Great Heart and the other men in the party go to kill the Giant Despair and his wife and to destroy their home. They succeed, releasing pilgrims from the Giant’s dungeon. They mount Despair’s head on a pole near the path to let other travelers know the danger there has been defeated.
The party continues to grow at every stopping point along the way. Mercy marries Matthew, and Christiana’s other three sons also take wives. Everyone they meet is amazed and joyful that Christiana, the wife of the famous pilgrim, has decided to take the same journey as her husband. Eventually, they make it to the King’s land and are called, one by one, across the river to the Celestial City.