The final volume opens in the midst of the Parisian insurrection of June eighteen thirty-two, centering on the barricade in the Rue de la Chanvrerie where a handful of devoted revolutionaries make their last stand. Jean Valjean joins the defenders, driven by his silent devotion to Marius, who is desperately in love with Valjean's adopted daughter, Cosette. When the barricade falls to the military assault, Valjean rescues the gravely wounded Marius by carrying him through the dark, perilous labyrinth of the Paris sewers.
Deep underground, Valjean navigates the treacherous stercoraceous maze, pursued by the relentless inspector Javert and intermittently crossing paths with the opportunistic Thénardier. Emerging from the subterranean depths onto the Seine bank, Valjean is intercepted by Javert, who experiences a profound moral crisis that shatters his absolute worldview, ultimately leading him to choose a path of unexpected mercy before his own tragic end.
Meanwhile, Marius is restored to his grieving grandfather, Monsieur Gillenormand, at his home in the Marais district. Surviving his catastrophic injuries, Marius is eventually reunited with Cosette, and the two are joyfully married with Valjean's quiet blessing.
As the narrative draws to its close, Valjean confesses his past as a galley convict to Marius, choosing a path of self-imposed isolation to protect Cosette's happiness. Grief-stricken and heartbroken, the young couple discovers the truth just as Valjean's earthly life fades, bringing his long journey of spiritual redemption to a peaceful conclusion.
