After a brief authorial digression about how his stuffy coworkers at the Custom House kept him from writing this book until he was fired, Hawthorne starts us off with a tour of the jail of the mid-17th century Massachusetts Bay Colony.
Inside the jail is one Hester Prynne, an adulteress who's just about to be released from prison so that she can be paraded through town, displaying the scarlet "A" that she's been forced to wear as evidence of her adultery. How do we know she's an adulteress? She's got a baby daughter, Pearl, but her husband has been away for two full years. Even we can do the math on that one. Despite all the shaming, Hester protects Pearl's father from punishment by refusing to give up his name.
The adultery parade (worse parade ever) is winding through town when… Hester Prynne's long-lost husband arrives in disguise! Once she's back in prison, he shows up and orders her to keep her mouth shut so he can carry out his Nefarious Plan of ferreting out and seeking revenge on her lover. For some reason, she agrees.
Hester's husband tells the townspeople that he's a physician named Roger Chillingworth. He's a smart fellow, so he realizes pretty quickly that the Reverend Arthur Dimmesdale is the likely father of Hester's baby. Obviously, his next step is to stalk the minister day and night. The minister is too afraid to confess his sin publicly, but he's feeling pretty guilty, not to mention antsy from Chillingworth's constant examination, and also maybe in a little pain from strange red mark that's on his chest
Oh, and this goes on for seven years.
Finally, Hester realizes that her husband has been doing some really wack psychological manipulation to the man she loves, and she reveals Chillingworth's true identity to Dimmesdale. They concoct a plan to settle in England and create a new life together. Yay, happy ending!
Or not. Dimmesdale ultimately backs out and confesses his sin to the townspeople on the scaffold where Hester was publicly shamed seven years earlier. He goes out with a bang by ripping his shirt open (à la Jean Valjean) to reveal the mark on his chest, just before dying.
That's all very dramatic and satisfying, but it's not the end. About a year later, Chillingworth dies and leaves all his money and property to Pearl, which means she and her mom can finally get themselves out of that awful community and return to England to build a new life. Yay, happy ending for sure this time!
Not quite. Years later, Hester actually returns to the colony, resuming the scarlet letter of her own will. When she dies, she's buried near the minister, and they share a gravestone marked with—what else?—the letter "A."