In which a pragmatic rubber stamp maker named Theophrastus Longuet, a man of sound mind and sceptic of the supernatural, recounts a peculiar and unsettling experience during a visit to the ancient Conciergerie that challenges his steadfast adherence to reason. Amidst the dark, timeworn stone corridors and haunted history, he discovers a mysterious scrap of paper written in his own handwriting, buried behind centuries-old walls, setting the stage for an enigmatic tale.

In which M. Theophrastus Longuet, accompanied by his charming wife and steadfast friend Adolphe, embarks upon a visit to the ancient and somber Conciergerie, seeking to enliven his mind through a tour of historical monuments dense with the echoes of past grandeur and tragedy. Their impressions shift from mild disappointment to uneasy intrigue as an extraordinary and mysterious incident unfolds within the shadowy recesses of the prison’s ancient cellars.

In which a sombre visitor delivers a mysterious sandalwood box to the narrator, professing it to be the bequest of the late Theophrastus Longuet, and then vanishes as enigmatically as he appeared. The narrator, initially wearied by the contents, soon finds himself drawn into a tale of such extraordinary nature that scepticism gives way to curious belief.