After reading the King’s letter, Christiana resolves to undertake the pilgrimage. Wisdom encourages her to leave soon, promising the King’s help along the way. That evening, Christiana shows the letter to her eldest brother, Matthew, who readily agrees to go. Her younger brothers, James and Joseph, also agree to the journey. The family decides to prepare in secret and depart in two days.

The day before their departure, Christiana’s friends visit and try to dissuade her, calling her “foolish” and reminding her of the dangers. Unmoved, Christiana and her brothers finalize their preparations. 

Early the next morning, the family quietly leaves the City of Destruction. Soon after, a girl named Mercy runs to catch up with them. Though she has not received a letter from the King, she wishes to join them. Christiana invites Mercy to travel with them to the Wicket-gate, where they can ask the gatekeeper if she may enter. Together, the group carefully crosses the Slough of Despond using the stepping-stones.

When the group arrives at the Wicket-gate, Christiana knocks, but a furiously barking dog frightens them. After she knocks again, the gatekeeper, Goodwill, appears and calms the dog. He warmly welcomes Christiana and her siblings into the Way of the King. Mercy, however, stays behind, afraid she will be turned away. When the gate closes, she panics and knocks frantically. Goodwill reopens the gate to find Mercy has fainted from fear. He carries her inside and revives her, assuring her that the King’s gate is open to anyone who knocks.

Goodwill allows the children to rest in his cottage. Mercy asks about the frightening dog, and Goodwill explains it belongs to the Wicked Prince, whose nearby castle is a source of trouble for pilgrims. After a meal, the children continue their journey. The path runs beside a high wall enclosing the Wicked Prince’s garden, and tree branches laden with fruit hang over it. Christiana warns against taking the fruit, but her brother Matthew ignores her and eats it.

Two menacing boys block the path and seize Christiana and Mercy. Christiana’s brothers are too scared to intervene, but Goodwill hears the girls cry for help and sends a man to assist. At the man’s approach, the two assailants climb the wall and escape into the Wicked Prince’s garden. The rescuer chastises Christiana for traveling without a protector, advising her to request a guide at the Interpreter’s house.

Weary from their journey, the children arrive at the house of the Interpreter. They receive a warm welcome from the Interpreter, who expresses happiness at meeting Christian’s friends.

The Interpreter shows the children the painting of the Good Shepherd. Next, in a dark room, they see a man obsessively raking sticks and straws, searching for a hidden treasure while ignoring an angel above him offering a golden crown. The Interpreter explains the man represents those who value worldly things over the King’s true riches. In the garden, he compares the King’s servants to different flowers, noting each has its own unique and valuable place.

The following morning, the Interpreter provides the children with new, white robes from the King’s treasury. The gift brings Mercy to tears, as it confirms her acceptance by the King. The Interpreter then assigns one of his servants, a young man in armor named Great Heart, to guide and protect them on their way to the Palace Beautiful. As they set off, Matthew lags behind the group, feeling sick from the fruit he ate but hiding his discomfort.

The pilgrims rest at the Cross. Nearby, they see the bodies of Simple, Sloth, and Presumption, the three boys little Christian once tried to awaken. Great Heart explains that the King eventually had the boys put to death as they continually tried to distract pilgrims from following the true path. Their bodies hang in chains as a warning. 

At the foot of the Hill of Difficulty, Great Heart points out a spring whose water has been fouled by the Wicked Prince’s servants. He shows the children how to let the dirt settle in a cup, allowing them to drink the purified water.

The climb up the Hill of Difficulty is arduous. Mercy and Joseph grow tired, and Joseph begins to cry from exhaustion and pain. Great Heart offers encouragement, telling them they are close to a resting place the King has provided. Soon they reach a pleasant arbor and sit down to rest. Christiana shares food that the Interpreter gave them. Great Heart assures the children that their present struggles will be forgotten once they reach the King’s City.

After their rest, the group continues up the hill. Christiana soon realizes she left a bottle of drink in the arbor, and James runs back to retrieve it. As they wait, Great Heart explains that pilgrims often forget things in the arbor because they relax too much. As dusk falls, they near the Palace Beautiful and hear the roaring of two lions belonging to the Wicked Prince, frightening the younger boys.

Great Heart chides the boys for their fear. Suddenly, a giant named Grim appears and blocks their path, ordering them to turn back. Grim is the master of the lions and a servant of the Wicked Prince. Remembering what Wisdom told her before she left home, Christiana cries out that the King will protect them. The giant laughs at her defiance. Great Heart draws his sword and prepares to fight the giant.

Great Heart battles and kills Giant Grim. With their master dead, the lions become passive, allowing the children to pass safely. They reach the gate of the Palace Beautiful, where the porter, Watchful, lets them in. The children beg Great Heart to accompany them for the rest of their journey. He agrees to ask his master, the Interpreter, for permission and returns home for the night. 

As Discretion has gone away to work for the King, Watchful summons her daughters. Prudence, Piety and Charity welcome Christiana and her party into the palace.

Christiana and Mercy are given the same room where little Christian once slept. That night, they hear beautiful singing from the palace residents. 

The next morning, Mercy recounts a joyful dream in which an angel gave her shining clothes and a crown before leading her to the King, who welcomed her as his daughter. The dream fills her with confidence that she is a true pilgrim.

The children are invited to stay at the Palace Beautiful for a month. During this time, Prudence educates the boys about the King. A local youth named Brisk becomes infatuated with Mercy and visits her frequently. However, Mercy perceives that Brisk does not serve the King and decides he is not a suitable friend. She politely distances herself by focusing on sewing clothes for charity whenever he visits.

Annoyed that Mercy is always busy with her charity work, Brisk stops visiting the palace. Meanwhile, Matthew, who has been feeling unwell since eating the forbidden fruit, becomes gravely ill. Christiana summons a doctor named Skill, who diagnoses Matthew with poisoning. Joseph recalls that Matthew ate fruit from the Wicked Prince’s garden, which the doctor confirms is the cause. Skill warns that Matthew may die without effective treatment.

Matthew is so ill that he initially refuses the doctor’s bitter medicine, but Christiana eventually persuades him to take it. After a night of severe pain, he begins to recover. The near-death experience humbles Matthew, making him more receptive to guidance. 

Before the pilgrims depart, Prudence’s sister, Piety, gives Christiana a golden anchor as a symbol of faith in the King. Great Heart has received permission from the Interpreter to continue the pilgrimage and arrives to lead them.

Prudence and her sisters accompany the pilgrims down the slippery path into the Valley of Humiliation. The valley is a beautiful and peaceful place, filled with lilies. Piety tells them that this is where little Christian fought the enemy Self and warns them to remain vigilant. Great Heart explains that it is the favorite valley of the Prince, the King’s son. However, no place on the journey is entirely safe from the servants of the Wicked Prince.

The pilgrims approach the Dark Valley. The path is narrow and treacherous, and the air is filled with unsettling noises, which terrify the younger boys. When James slips, Matthew saves him from falling. Great Heart then revives James with Skill’s medicine. Christiana clutches the golden anchor, drawing strength from the symbol of her faith.

Inside the Dark Valley, a lion appears and roars at the pilgrims, but it retreats when Great Heart stands ready to fight. Shortly after, their path is blocked by a deep pit while a thick, disorienting mist envelops them. Great Heart suspects the pit is an illusion created by the Wicked Prince and advises everyone to stand still and pray. Their prayers are answered as the mist clears, revealing the path is solid and safe. After passing through a section of poisonous vapor, Great Heart warns that they are approaching an area filled with hidden snares.

Near the end of the valley, the pilgrims see the body of a man named Heedless, caught in a snare. As they approach a cave, a young giant named Maul emerges. Maul accuses Great Heart of being a robber who leads children away from their homes. Declaring himself a servant of the King, Great Heart engages the giant in a fierce battle. Though Great Heart is knocked down, he rises and wounds Maul. The fight pauses, and the pilgrims pray for strength, which seems to frighten the giant, who then prepares to renew his attack with even greater ferocity.