The Confessions of Joseph Blanchard is a contemporary story of obsessive love, sexual transgression and tragic loss. Bachelor and professional accountant Joseph Blanchard has led a socially active though emotionally cautious life into his late thirties. When he discovers that his beautiful nineteen-year-old cousin Sophie, a talented concert pianist, is in love with him, he finds he is helpless to resist her youthful charms, and against his better judgment embarks upon a passionate affair.

As a safeguard against causing pain to her parents, the two lovers conspire to keep their relationship secret. For a while they are happy. But Sophie's performing career compels her to spend time in the company of other musicians, many of them young men. Consumed by jealousy, Joseph allows rage to seize control, with tragic results.

Grieving, he sets about to destroy all evidence of the affair. But when a family secret is exposed, it reveals the past in a new light. In the end, his health in decline and with nothing left but memories, he discloses his secret to a confidant.