The Scarlet Letter is the story of Hester Prynne, a young Puritan woman who has had an illegitimate child. Despite being publicly humiliated by wearing a large scarlet letter 'A' on her dress, Hester refuses to reveal the identity of her child's father, even as the vindictive newcomer Chillingworth becomes determined to make her confess. This story explores the themes of sexual liberation, sin, and vengeance.
Pearl sees the two of them together and refuses to join them until her mother puts the "A" back on her dress, and puts her hair up again. Hester does so and Pearl joins them, but does not co-operate. Dimmesdale tries to kiss her to show his willingness to get along, but Pearl tries to wash off the kiss in the brook. The two adults realize the joyous meeting is not going to happen and they make plans for the future.
While Hester is assuring Dimmesdale that Pearl will love him, Dimmesdale talks about how he had seen his face in Pearl's, and was always afraid that other people would see the same and as a result uncover the truth. Pearl stays on the opposite side of the brook, as if she is unable to reenter the world that Hester and Dimmesdale occupy. Hester encourages Pearl to come to them, but Pearl refuses. Hester is puzzled, and Pearl begins to point. Hester realizes that Pearl sees that the "A" is missing, and will not come until it is back in place. She replaces it, despite the burden that it brings with it. She puts her hair up again and Pearl finally joins them.
Hester tries to introduce Pearl to Dimmesdale and get them to get along. Pearl either from jealousy, or from impression of his inconsistency, refuses to be friends with him. He gives her a kiss and she attempts to wash it off in the brook. The meeting is not working, so Hester and Dimmesdale make a few plans and then decide to return to the settlement.
Dimmesdale returns to the settlement alone, in advance of Hester and Pearl and reviews the plans that he and Hester made. They planned to sail to Bristol on a Spanish ship currently docked in Boston. Dimmesdale has time to give the sermon on Election Day, which is an honor for him. He is energetic and excited and makes his way home through the marketplace. He is confronted with four opportunities in which he is tempted to act improperly, but he manages to resist. He is confused by his willingness to be rude, and considers it an effect of his new plan to leave Boston. He returns to his study and is confronted by Chillingworth. Dimmesdale releases him from his duties as personal physician, and Chillingworth leaves a vague threat. Dimmesdale sets to rewriting his Election Day sermon.
Dimmesdale returns to town alone, in advance of Hester and Pearl, and reviews the plans that he and Hester made. Hester would talk to the captain of a Spanish ship docked at the port that is getting ready to sail to Bristol and secure places for the three of them on it. They will sail in about four days, which allows Dimmesdale to deliver the Election Sermon. The sermon, which was given after the election of new magistrates in Boston, was an honor for whomever was chosen to deliver it. Dimmesdale, full of energy from the recent events, is on his way home when he meets a deacon from his church. He feels the urge to say something improper, but manages to resist. This happens twice more on his journey, as he next meets the oldest woman in his congregation, and then meets a young virgin who belongs to his church. On both occasions he feels the need to say something improper, or feels the inability to say what he should say. His last temptation is to teach a few vulgar words to a group of children playing nearby.
Dimmesdale escapes these situations without planting any seeds of evil in any pure hearts, and he considers the feelings that he is experiencing. He wonders if the decision that he made in the forest was in fact a pact with the devil. At this moment, Mistress Hibbins appears, and tells him that she knows that he has been in the woods. She insinuates that it is clear that Dimmesdale does one thing during the day and another at night. Dimmesdale is offended, but realizes that there is a little bit of truth in what Mistress Hibbins says.
Dimmesdale finally gets home, and thinks about his new knowledge of himself and humanity in general. He is in his study, now surrounded by familiar things, but he is a different man. Chillingworth comes in and Dimmesdale lets him know that he no longer has any need for his services. Chillingworth suggests that Dimmesdale is planning to leave, which he neither affirms or denies, mentioning that with his weak health he may very well leave the earthly realm for the heavenly one. Chillingworth offers to help Dimmesdale with his election sermon, which Dimmesdale rejects and sets to writing a new one himself.
Hester, convinced that a happy ending is possible for her and Dimmesdale, looks forward to Pearl joining them and forming a happy family unit. They both see their union in Pearl and are finally able to consider the most powerful symbol of their experience with enthusiasm rather than fear. Pearl returns, but does not accept the change that Hester and Dimmesdale have forced onto the situation. She remains honest to their identities, and insists Hester do the same by reattaching the letter "A" and putting her hair up. Pearl is described as existing in another world, separated from Hester and Dimmesdale. She stands across the brook from them, and the brook, which carries all the secrets and burdens of experience, separates the one who understands the inevitability of honesty from the two who believe they can challenge their fate. Pearl is the effect of their union; they do not see that in her they are united forever, and it is only through her that they will be together. Hester puts the letter on to pacify Pearl, who immediately confronts Dimmesdale with the question of his standing with them in the daytime. She suggests that it is only in this way that three will ever stand together in the daylight.
Dimmesdale is a changed man, energized by his time in the forest. He returns to town and even his own church looks strange to him. He interacts with people in an entirely different way, and the freedom of living without secrecy seems to give him a new outlook. In the forest he looked at the world through the eyes of a woman who had been isolated from society for seven years, and he is able to see his situation from another angle. He is free of the constraints that bound him to his false penance, and although confused by his feelings, he is buoyed up by them. Mistress Hibbins recognizes the change, and approaches him about his time in the forest. His conversation with her causes a realization that he has betrayed something by giving in to a delusion of happiness. He reaches his study, and standing among his familiar books and papers becomes aware of the change that has happened. He has acknowledged his sin and as a result gained Hester's sensitivity and greater knowledge of the complexity of guilt and sin. At this moment it seems that his next action becomes clear, and after confronting Chillingworth, who predicts Dimmesdale's departure, suggests that he does not plan to leave with Hester, but make his way to another realm altogether.