This is an extremely short synopsis (in my opinion) from the Complete Symphonic Recording of Les Mis. It's not verbatum because there were some things I just had to change (ex. giving the specifics of the dear Inspector's death).
Prologue: 1815, Dinge
After 19 years on the chain gang, Jean Valjean finds that the ticket-of-leave he must display condemns him to be an outcast. Only the Bishop of Dinge treats him kindly and Valjean, embittered by years of hardship, repays him by stealing some silver. Valjean is caught and brought back by the police and is astonished when the bishop lies to the police to save him. Valjean decides to start life anew.
1823, Montreuil-sur-mer
Eight years have passed and Valjean, having broken his parole and changed his name to Monsieur Madeleine, has become a factory owner and mayor. One of his workers, Fantine, has a secret illegitimate child. When the other women discover this, they demand her dismissal.
Desperate for money to pay for medicines for her daughter, Fantine sells her locket, her hair, and then joins the whores in selling herself. Utterly degraded, she gets into a fight with a prospective customer and is about to be taken to prison by Javert when "The Mayor" arrives and demands that she be taken to the hospital instead.
The Mayor then rescues a man pinned beneath a cart. Javert is reminded of the abnormal strength of convict 24601 Jean Valjean, who he says, has just been recaptured. Valjean, unable to see an innocent man go to prison, confesses that he is prisoner 24601.
At the hospital, Valjean promises the dying Fantine to find and look after her daughter Cosette. Javert arrives to arrest him, but Valjean fells Javert and escapes.
1823, Montfermeil
Cosette has been lodged with the Thénardiers, who horribly abuse her while indulging their own daughter, Eponine. Valjean pays the Thénardiers to let him take Cosette away to Paris.
1832, Paris
Nine years later, there is unrest in the city because of the likely demise of the popular leader General Lamarque, the only man left in the government who shows any feeling for the poor. A street gang led by Thénardier and his wife sets upon Jean Valjean and Cosette. They are rescued by Javert, who does not recognise Valjean until he has gone. The Thénardier's daughter, Eponine, who is secretly in love with the student Marius Pontmercy, reluctantly agrees to help him find Cosette, with whom he has fallen in love.
News of General Lamarque's death circulates in the city and a group of politically minded students stream out into the streets to whip up some support for a revolution.
Cosette is consumed by thoughts of Marius, with whom she has fallen in love. Eponine brings Marius to Cosette and then prevents an attempt by her father's gang to rob Valjean's house. Valjean, convinced it was Javert lurking outside his house, tells Cosette they must prepare to leave the country.
The students prepare to build the barricade. Marius, noticing that Eponine has joined the insurrection, sends her away with a letter to Cosette, which is intercepted by Valjean. Eponine 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 Eponine is shot in the head and dies in Marius's arms.
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 all of the rebels are killed.
Valjean escapes in to the sewers with the wounded, unconscious Marius on his back. 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 the hospital. Javert lets Valjean go and, his unbending principles of justice having been shattered by Jean Valjean's own mercy, he jumps off of the bridge over the Seine River. 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 Valjean dies.
