Set in post-1968 Paris, the film follows Alexandre, an aimless and intellectually verbose young man who drifts through life with little purpose. He is entangled in a complicated romantic dynamic with his live-in girlfriend, Marie, an older woman who financially supports him but endures his emotional oscillations with mixed acceptance and frustration. Despite this relationship, Alexandre embarks on a new emotional venture, becoming infatuated with Veronika, a young nurse he meets in a café. Juggling these two relationships, he candidly shares his intimate life with both women—expressing feelings of alienation while testing the limits of their patience and understanding. Through long-winded monologues and candid dialogues, Alexandre explores the fading ideals of love and liberty promised by the sexual revolution, along with his own disillusionment and existential angst.

Marie is both nurturing and possessive, providing variety to the capricious attention Alexandre diverts between the two women. Veronika brings her own complex personality to the triangle, as a confident yet vulnerable individual attracted to Alexandre's poetic yet flawed nature. As time progresses, the relationships fluctuate between tenderness, jealousy, and exasperation. Both women offer contrasting perspectives on femininity and empowerment in the face of Alexandre's inconsistency. The evolving dynamics serve as a microcosm for the social and personal upheaval characteristic of the era. As each character confronts their beliefs and insecurities, the story delves deep into explorations of love's limitations, freedom's constraints, and the search for meaning amidst modern disillusionment.