After Thénardier's arrest, Marius immediately leaves his room and moves in with Courfeyrac, who receives him with the simple hospitality of a true friend. Marius has two reasons for the move. First, the viciousness he has witnessed makes him loathe the Gorbeau tenement; and second, he does not want to testify against Thénardier. As the months go by, Marius sinks back into a state of depression. The happiness that he has glimpsed has again vanished. This time the loss of his beloved seems irreparable; he cannot find even the most tenuous link with her. He is disturbed, also, by her "father's" equivocal behavior. The old gentleman's refusal to call for help and his quiet escape are highly suspicious.
Material difficulties compound his misery. Once again Marius is plagued by poverty. Too discouraged to work, he has quit his job and abandons himself to a dangerous reverie that increases his lethargy. Absorbed by the vision of his lost love, he contemplates impassively his inexorable disintegration. Unfit for practical activities, he is only capable of absurd and romantic gestures. In a notebook he writes ethereal love letters destined never to be read. Because the Thénardiers called the girl he loves "the Lark," her Montfermeil nickname, he makes regular pilgrimages to an isolated area called "the Field of the Lark."
Hugo now takes us to visit Javert, who is not happy. Thénardier's prisoner, who would probably have been an interesting prize for the police, has vanished, and two of the gangsters — Montparnasse and Claquesous — have slipped between his fingers, too. The latter's escape is particularly humiliating since it was engineered in the police vehicle itself. The rest of the gang are also far from inactive. One of its imprisoned members, Brujon, is engaging in suspicious maneuvers. He dispatches three messages to confederates on the outside. One day a guard catches him in the act of writing a letter, but the letter disappears before the guard can seize it.
The next day a note wrapped in a ball of bread reaches Babet, one of the leaders of the Patron-Minette gang. From Babet, it goes to Eponine, who inspects the house in the Rue Plumet. As an answer, Eponine returns a biscuit, which in the mysterious code of the underworld means "nothing doing." This abortive criminal plot has totally unexpected consequences. It acquaints Eponine with Cosette's whereabouts, and this piece of information soon changes the latter's destiny and that of her lover Marius.
Marius' old friend Mabeuf, the churchwarden, has been suffering a decline that resembles that of Marius himself. His major source of income, his book Flora of Cauteretz, is not selling at all. His experiments on indigo are a failure. His breakfast is reduced to two eggs, and often it is his only meal. One peaceful evening, Mabeuf sees a strange apparition. Exhausted from his day's work on his indigo experiments, he rests in his garden with a book in his hands while he anxiously studies his magnificent rhododendron, threatened by drought. He would like to water his flowers, but he doesn't even have the strength to unhook the chain from the well. Unexpectedly, he has a bizarre visitor, a ragged, undernourished girl who proceeds to water his whole garden for him. As a reward, she asks for Marius' address and disappears as soon as she has learned it.
A few days later, Marius, restless and unable to work, has gone on his usual pilgrimage to the Field of the Lark. Sadly he is thinking of "her," and his sadness is aggravated by self-reproach. His reverie is broken by Eponine's appearance. She addresses him in a babbling mixture of delight, naive questions, explanations, and compassion. The girl is obviously and pathetically in love with him. At last, since he shows no interest in her as a person, she tells him that she knows Cosette's address. Marius is ecstatic and, blinded by love, ignores the tragic effect his happiness has on Eponine. He is concerned only with his sweetheart's safety and makes Eponine promise she will not reveal the address to her father. She reminds him that he has promised her a reward, and he gives her five francs. Somberly she drops it with the comment, "I don't want your money."
In the suburb of Saint Germain is located an unobtrusive little house, the former love nest of an eighteenth-century magistrate. Among its features, there is a secret exit onto another street which allowed the amorous but prudent judge to visit his mistress without arousing suspicion. In October 1829, Jean Valjean has rented the long-vacant house under the name of Fauchelevent, reopened the secret passageway, and installed Cosette and an old servant, Toussaint, in this new residence. In spite of his happiness in the convent, he decided after much thought to leave Little Picpus. He felt that he owed it to Cosette to provide her with a normal life in spite of the dangers this would present to his personal safety. As an added precaution, he has rented two other old apartments in Paris as potential retreats; one is that to which Marius previously traced Cosette.
Except for a few luxuries for Cosette, the pair lives modestly and above all discreetly. They take walks in the Luxembourg Gardens, go to mass, give generously to the beggars at the door of the church, and visit the poor and sick. Valjean serves in the National Guard, an obligation that he welcomes since it gives him an aura of respectability. Buoyed by Cosette's companionship, Valjean enjoys the simplicity of his new life.
The young girl is happy too. Her garden is a world of endless discoveries. In Valjean she finds an interesting friend who shares with her the fruits of his wide readings; he is her universe, both father and mother to her, and she fusses over his cold room and his Spartan diet. She hardly remembers her past and has completely forgotten her mother, for Valjean never mentions her. A mysterious instinct warns her that her origins are a subject better left unmentioned.
But unsuspected dangers threaten their tranquility. Cosette is about to enter adolescence, an age of temptations and longings for which she is completely unprepared. Her ignorance, carefully protected by the convent, only enhances the intensity of desires that she experiences without understanding. Valjean, a bachelor quite unused to women, is unable to help her.
One day, Cosette suddenly realizes that she is very pretty. What her mirror has hinted is confirmed by the comments of a passerby and the observations of the old servant Toussaint. With inexpressible satisfaction, she realizes that her skin is a satiny white, her hair lustrous and beautiful, her blue eyes splendid. Valjean, however, is dismayed by her beauty; he is dimly aware that any change threatens his happiness and that another may some day steal Cosette from him. Nevertheless, he does not prevent her from ordering an elegant new wardrobe nor from parading her gracefulness in public.
It is at this time that Cosette meets Marius in the park. Subconsciously she notes his good looks, his air of intelligence, his gentleness. Then their eyes meet, and his glance produces the same effect on her as hers on him. Love, in turn, unleashes a multitude of incomprehensible and contradictory emotions in her. At first she is angry at Marius' apparent indifference, then she boldly approaches him in the park. Later, melancholy overtakes her, and she suffers the traditional sleeplessness, agitation, and fever. Still her love remains distant, "a mute contemplation, the deification of a stranger."
Valjean, too, is aware of Marius. Unlike Cosette, he views him as a threat and lays traps for him. He changes benches, drops his handkerchief, comes alone to the park. When Marius' reactions betray his interest in Cosette, Valjean grows hateful and ferocious and watches him like "a hound looking at a thief." When Marius makes the mistake of questioning the doorman, Valjean moves to the Rue Plumet without leaving a trace. Cosette accepts her fate without complaint; indeed, she has no vocabulary to express any of the feelings she now experiences. But she falls into a profound despondency that becomes deeper as the separation from Marius lengthens. Valjean notices her sadness and is heartbroken, but he does not know how to cure it. Tragically, Cosette and her foster father come to hurt each other deeply in spite of their mutual love.
One morning, a somber incident deepens their gloom. As is their wont, they are taking a walk to enjoy the glory of sunrise. For a moment they are consoled by the serenity of the hour. Then a harsh noise disturbs their peace: it is the forerunner of a dreary spectacle, a long convoy of prisoners. A mass of convicts, sinister and dehumanized, are being transported to the galleys on seven tumbrils escorted by rows of equally sinister guards. The scene is one of degradation, brutality, misery, and filth. Valjean is petrified by this vision from his past, and the sensitive Cosette is equally frightened.
In these two books, through many rapid changes of scene, Hugo is maneuvering all his characters toward a crisis and preparing also for the denouement of the love story in the next part. Five of his characters — Marius, M. Mabeuf, Eponine, Cosette, and Jean Valjean — are undergoing a period of sorrow and doubt. For Marius, this period of inactivity and passivity is a prelude to a violent reaction that will once more reunite him with the realities of life and decide his destiny for good or ill. The despair of Eponine and M. Mabeuf, which has more valid causes, will also produce dramatic decisions and drastic consequences. Cosette's unhappiness deepens and strengthens her feeling for Marius, and by learning to bear sorrow with patience, she matures from girl into woman. As for Jean Valjean, his anger and grief are a normal response to the foreknowledge that yet one more sacrifice will soon be demanded of him, and this the greatest sacrifice of all.
Skillfully, Hugo uses Eponine not only to win our sympathy but to further plot and character development. A waif just out of prison, she is a figure pathetic enough to cause any bourgeois to subscribe promptly to public education and child welfare, but she also serves as a link between the criminals, Marius, M. Mabeuf, and Cosette and Jean. Finally, her love for Marius, which Marius ignores, points up the egoism of his blind devotion to his unknown love — a devotion that has already made him idle and neglectful of his own future. Marius, young hero though he is, is far from perfect — perfection is a privilege that will ultimately be reserved for the elderly Jean Valjean.
Jean Valjean, however, is right to fear him, just because he is young and in love and because nature is therefore on his side. Good parenthood always ends in a painful separation because it is a parent's function to prepare the child to leave home. Jean Valjean has courageously taken the first step in this direction already by taking Cosette out of the convent and allowing her the liberty to choose what her future life will be. Nature, in making her beautiful, takes the next step; Marius is simply the inevitable conclusion of a series of developments.
The garden of the Rue Plumet is the image of Cosette's spirit — innocent, beautiful, and wild — and Jean Valjean has until now been privileged to share its springtime joy. Cosette's true companion, however, is on his way, and once he arrives Jean Valjean will again be shut out in the shadows of his past, as the scene with the convicts at the Barrière du Maine implies.