In the summer of 1890, Curé Labelle pushed for colonization. To flee Séraphin and the woman he loved, Donalda, Alexis got married and settled on a piece of land. Everyone joins forces to take their revenge on the hateful Séraphin.

Pierre Chambrac, a French industrialist, and Canadian Paul Laforêt, two former brothers in arms, meet again by chance in Paris five years after the end of World War II. Pierre is engaged to a beautiful foreign young lady by the name of Helen Bering. He introduces her to his friend, which seems to trouble him. To his amazement, Helen and Paul disappear without notice. Pierre, who was beginning to feel jealous, sees his suspicion confirmed. He decides to fly to Montreal where he thinks the couple has taken refuge. Once there, he learns that his dear Helen is actually a criminal and that Paul is a policeman whose duty was to arrest her.

Filmed in French, this Canadian film was based on a popular Quebec-based radio serial. The man of the title is miserable miser Seraphim (Hector Charland). Misanthropic to the point of insanity, Seraphim takes great pleasure in destroying the lives of everyone with whom he comes in contact. His current target is Alexis (Guy Provost), the ex-lover of Seraphim's long-suffering wife Donalda (Nicole Germain). Taking into consideration its daytime-drama source, it's understandable that Un Homme et Son Peche is plotted and paced like a soap opera. Star Hector Charland had previously spent 10 years portraying Seraphim on radio, so he's got plenty of "mean" at his disposal for this big-screen spin-off.