After the death of the Count of Borel, his wife and daughter Solange had to leave - fifteen years ago - the magnificent Domaine de la Châtaigneraie. A serious disagreement had separated the parents of the little girl at the time. His mother remains wounded....

James Spinder, a rather mysterious buyer, is now the master of the castle. Solange manages one day to get into the Chestnut grove, gleaning memories...

Mr. Spinder welcomed the girl with kindness. He even gave her an intimate notebook from his father. Some kind of confession.... Solange discovers that a host of Mr. Spinder, the seductive Maurice de Rouvalois, is the last one who saw the Count of Borel alive.

Why was Maurice hiding this meeting from Solange, who was very fond of him? Did he make a promise to the Count of Borel?

Disoriented, in love, unhappy but determined, Solange doubts her father's death and swears to know the whole truth...