As his cab takes him without destination through the streets of the Latin Quarter, Marius is hailed by a fellow student, Bossuet. He tells him of his difficulties, but Bossuet, though full of goodwill, is unable to help since he himself is homeless. Another classmate, Courfeyrac, however, comes to the rescue and suggests a room in the Hotel de la Porte Saint Jacques, where he himself lives. With the spontaneity of youth, the two students immediately become friends.
This friendship is to have a profound effect on Marius' intellectual life. Courfeyrac belongs to a radical group, the Friends of the A.B.C. (This is a serious pun; the pronunciation of A.B.C. in French is the same as abaissé, the oppressed.) Inevitably, he introduces his new friend and Marius is caught up in a tide of new ideas. Nothing is respected in these wild and irreverent discussions. Not even Napoleon is spared. When the word "crime" is applied to his empire, Marius, usually reserved, explodes in a passionate harangue and eloquently defends Napoleon's career, but his concluding question — "What is greater than Napoleon's conquests?" — is squelched by a quiet retort, "To be free."
Marius' new convictions are shaken, but not enough to make him embrace the more radical ideas expounded around him. He suffers from intellectual uncertainty and isolation. Material difficulties aggravate his unhappiness. He has no job but proudly refuses help from home. To pay his most pressing bills, he sells his few possessions and leaves the hotel.
Having reassured us somewhat by explaining the Colonel Pontmercy who appeared out of nowhere in Part Two, and by connecting Marius with him, Hugo now takes us to meet yet a third group of unknown characters, the Friends of A.B.C. However, all these strangers — Gavroche, Marius, Enjolras and his friends, and even M. Mabeuf of Book V — are only apparently introduced at random. All their destinies are converging on one historic moment where they will also become entangled with the fate of Jean Valjean.
Hugo describes each member of the student group with affection and understanding: Enjolras the militant, Combeferre the genial philosopher, Prouvaire the artistic idealist, Feuilly the intelligent workman, Courfeyrac the "good guy," Bahorel the irrepressible, Bossuet (Laigle) and Joly the misfits, and Grantaire the cynic. Enjolras is a particularly interesting study since he is one of the first portrayals in literature of that characteristic nineteenth-century angel of death, the political idealist, the flawless fanatic, the "pure" Marxist or anarchist. What really justifies the attention Hugo devotes to these young men, however, is that they are all going to die.
It will be noted that Marius' political evolution follows that of Hugo himself — from the royalism of his Breton mother to the mildly liberal Bonapartism of his heroic father to a firm devotion to Republican principles.