Pierre Lachenay, a successful and married literary magazine editor, embarks on a publishing trip to Lisbon. During his journey, he meets Nicole, an attractive and free-spirited flight attendant. The two share a fleeting yet intense attraction that quickly blossoms into a passionate affair. Despite the thrill of this new relationship, Pierre struggles with guilt and the complex logistics of maintaining his double life. The tenderness between them contrasts sharply with the mounting deception he must weave to keep his marriage intact.

As Pierre's affair with Nicole deepens, the strain on both his professional life and marriage becomes more pronounced. His wife, Franca, emotionally committed and suspicious by nature, begins to pick up on the subtle shifts in Pierre's behavior. Meanwhile, Pierre becomes increasingly torn between his growing affection for Nicole and the responsibilities to his family. As tensions rise, Pierre must confront the unsustainable nature of his deception, with each choice threatening to unravel the life he once carefully curated.