The story begins on Epiphany (6 January), 1482, the day of the Feast of Fools in Paris, France. Quasimodo, a deformed hunchback who is the bell-ringer of Notre Dame, is introduced by his crowning as the Pope of Fools.
Esmeralda, a beautiful Gypsy with a kind and generous heart, captures the hearts of many men, including those of Captain Phoebus and Pierre Gringoire, a poor street poet, but especially those of Quasimodo and his adoptive father, Claude Frollo, the Archdeacon of Notre Dame. Frollo is torn between his obsessive love and the rules of the church. He orders Quasimodo to kidnap her, but the hunchback is captured by Phoebus and his guards, who save Esmeralda.
Quasimodo is sentenced to be flogged and turned on the pillory for one hour, followed by another hour's public exposure. He calls for water. Esmeralda, seeing his thirst, offers him a drink. It saves him, and she captures his heart.
Esmeralda is later charged with the attempted murder of Phoebus, whom Frollo actually attempted to kill in jealousy after seeing him about to have sex with Esmeralda, and is tortured and sentenced to death by hanging. As she is being led to the gallows, Quasimodo swings down by the bell rope of Notre Dame and carries her off to the cathedral under the law of sanctuary.
Frollo later informs Pierre Gringoire that the Court of Parliament has voted to remove Esmeralda's right to sanctuary so she can no longer seek shelter in the church and will be taken from the church and killed. Clopin, a street performer, hears the news from Gringoire and rallies the Truands (criminals of Paris) to charge the cathedral and rescue Esmeralda.
When Quasimodo sees the Truands, he assumes they are there to hurt Esmeralda, so he drives them off. Likewise, he thinks the King's men want to rescue her, and tries to help them find her. She is rescued by Frollo and her phony husband Gringoire. But after yet another failed attempt to win her love, Frollo betrays Esmeralda by handing her to the troops and watches while she is being hanged.
When Frollo laughs during Esmeralda's hanging, Quasimodo pushes him from the heights of Notre Dame to his death. Quasimodo then goes to the vaults under the huge Gibbet of Montfaucon, and lies next to Esmeralda's corpse, where it had been unceremoniously thrown after the execution. He stays at Montfaucon, and eventually dies of starvation. About eighteen months later, the tomb is opened, and the skeletons are found. As someone tries to separate them, Quasimodo's bones turn to dust.
