The students prepare to build the barricade. Marius, noticing that Éponine has joined the insurrection, sends her away with a letter to Cosette, which is intercepted by Valjean. Éponine decides to rejoin her love at the barricade.

The barricade is built and the revolutionaries defy an army warning to give up or die. Javert is exposed as a police spy. In trying to return to the barricade, Éponine is killed.

Valjean arrives at the barricade in search of Marius. He is given the chance to kill Javert but instead lets him go. The students settle down for a night on the barricade and, in the quiet of the night, Valjean prays to God to save Marius. The next day the rebels are all killed.

Valjean escapes into the sewers with the unconscious Marius. After meeting Thénardier, who is robbing the corpses of the rebels, he comes across Javert once more. He pleads for time to deliver the young man to hospital. Javert lets Valjean go and, his unbending principles of justice having been shattered by Valjean’s own mercy, he kills himself.

Unaware of the identity of his rescuer, Marius recovers in Cosette’s care. Valjean confesses the truth of his past to Marius and insists he must go away.

At Marius and Cosette’s wedding, the Thénardiers try to blackmail Marius. Thénardier says Cosette’s ‘father’ is a murderer and as proof produces a ring which he stole from the corpse the night the barricade fell. It is Marius’s own ring and he realises it was Valjean who rescued him that night. He and Cosette go to Valjean where Cosette learns for the first time of her own history before the old man dies.