The usual course of life of St. Petersburg antique dealer Daniil Dakh is disrupted by a morning telephone call. Someone offers him to purchase a third notebook, unknown to Dostoevsky's biographers, with notes from Apollinaria Suslova, the writer's fatal mistress. Arriving at the appointed place, Dakh does not find the owner of the mysterious notebook there... but meets there one who inexplicably reminds Suslova. What is this - a sophisticated prank or a mystical coincidence? In search of answers, the antiquarian and his mysterious companion repeat the routes and painful relationships of Dostoevsky and Suslova... As a result, the desired notebook ends up in Dakh’s possession. But...