Thénardier’s daughter Eponine, who is in love with Marius, helps Marius discover Cosette’s whereabouts. Marius is finally able to make contact with Cosette, and the two declare their love for each other. Valjean, however, soon shatters their happiness. Worried that he will lose Cosette and unnerved by political unrest in the city, Valjean announces that he and Cosette are moving to England. In desperation, Marius runs to his grandfather, M. Gillenormand, to ask for M. Gillenormand’s permission to marry Cosette. Their meeting ends in a bitter argument. When Marius returns to Cosette, she and Valjean have disappeared. Heartbroken, Marius decides to join his radical student friends, who have started a political uprising. Armed with two pistols, Marius heads for the barricades.

The uprising seems doomed, but Marius and his fellow students nonetheless stand their ground and vow to fight for freedom and democracy. The students discover Javert among their ranks, and, realizing that he is a spy, Enjolras ties him up. As the army launches its first attack against the students, Eponine throws herself in front of a rifle to save Marius’s life. As Eponine dies in Marius’s arms, she hands him a letter from Cosette. Marius quickly scribbles a reply and orders a boy, Gavroche, to deliver it to Cosette.

Valjean manages to intercept the note and sets out to save the life of the man his daughter loves. Valjean arrives at the barricade and volunteers to execute Javert. When alone with Javert, however, Valjean instead secretly lets him go free. As the army storms the barricade, Valjean grabs the wounded Marius and flees through the sewers. When Valjean emerges hours later, Javert immediately arrests him. Valjean pleads with Javert to let him take the dying Marius to Marius’s grandfather. Javert agrees. Javert feels tormented, torn between his duty to his profession and the debt he owes Valjean for saving his life. Ultimately, Javert lets Valjean go and throws himself into the river, where he drowns.