Philippe de Montfaucon, David Niven, the hereditary owner of an ancient Bordeaux estate, returns from Paris to the crumbling chateau of Bellenac after three fruitless years in the vineyards. He shares the burden of the land with his devoted wife, Deborah Kerr Catherine, and their two children, Jacques Robert Duncan and Antoinette Suky Appleby. A summons from the valley ushers them into a world where superstition lingers like a shadow; at the center of it all, a sinister priest presents Philippe with a strange amulet that seems to bind fate to old, blood-soaked ritual. The family’s arrival is marked by a small, almost ritual arc: a dove is released, a tethered omen that foreshadows what lies ahead.
Late at night, Catherine encounters Odile, [Sharon Tate], and Christian [David Hemmings], who carry an impaled dove into a candlelit room where robed figures sit. The birdship is offered first to an altar whose cross mirrors the amulet and then to a figure at the head of the circle. The doors slam shut, and an old man warns Catherine to take her children and flee. Philippe is quick to dismiss her concerns, insisting that the valley’s so-called legends are nothing more than ancient superstition, even as his aunt Estelle [Flora Robson] warns that Christian is a very wicked boy and Odile is no better. Catherine’s growing unease deepens as she suspects a dangerous fixation on her son Jacques.
To understand what she’s facing, Catherine turns to a trusted ally: family friend Jean-Claude Ibert [Edward Mulhare], who helps uncover a long, grim Montfaucon history. He reveals that twenty-two heads of the family have died under mysterious circumstances dating back to the 1200s, a pattern that shadows Philippe’s lineage as surely as the amulet itself. Catherine’s investigation leads her to the tomb of Edouard de Montfaucon, where a carving matches a painting in the chateau and an inscription speaks of twelve dancers. Emerging from the mausoleum, she is pursued by robed figures, faints, and wakes with Philippe by her side, offering a sedative and a kiss that blurs the line between care and complicity.
Her visions grow more nightmarish, and she finds herself locked in the bedroom. After breaking the shutter, she signals Estelle, who sends her maid to help. Yet the doctor’s diagnosis—she has been drugged with belladonna—offers little comfort. The community gathers for the festival known as Les Treize Jours (The Thirteen Days), and in the church, Père Dominic prays in Latin while Philippe and Estelle’s family take their places in the pews. A chilling moment arrives when twelve robed figures form a circle outside Philippe and sway in unison as Philippe kisses Jacques, provoking gasps from the crowd. The priest’s paraphrase of Genesis 1:11 echoes through the ceremony as the crowd witnesses a ritual that seems to presage doom:
> Let the Earth bring forth vines, yielding fruit after its kind, whose seed is in itself, upon the earth, and the Word was God
Estelle then reveals a horrifying family secret: Alain, Philippe’s father and Estelle’s brother, did not die but fled to the tower above, where he warns that the thirteen days and the dancers are a living god’s ritual—an offering for blood sacrifice in this strange town. Père Dominic, a pagan priest, holds court over a Black Mass, and Philippe’s kiss of Jacques seems to signal an unavoidable fate.
As the revelation deepens, Philippe speaks with Catherine in a detached cadence, admitting that the ritual cannot be stopped and that no one will believe her testimony. She races to intervene, chasing the group through the forest, but Christian intercepts the path and strikes down Philippe in the heart of the woods. His body is carried back through the vineyards to the heart of Bellenac, while Jacques watches the tragedy unfold from a distance.
A torrential rain bathes the landscape as Jean-Claude reads a newspaper account of the supposed accident. The family prepares to flee, but Jacques hesitates to leave without his watch. Inside, a priest awaits him, offering the amulet once more as the boy kisses it and climbs back into the car. The final image lingers on Odile, seated outside in a windstorm, smiling with a knowing, enigmatic calm as the car finally pulls away from the chateau.
