Andrey Kovrin, a holder of a master’s degree has nerve disorder. On the advice of the doctor he decides to go to the village. This decision coincides with an invitation for a visit from his childhood friend Tanya Pesotska, who is living with her father, Yegor Semyonitch in the estate of Borisovka. April. Description of vast collapsing house of Pesotsky with an ancient park in the English style. Yegor Semenovich is a passionate gardener, devoted his life to his garden, and not knowing whom to pass his farm before his death. The night Kovrin comes Yegor Semenovich and Tanya sleep alternately: watching workers who save the trees from frost. Kovrin and Tanya go to the garden, remembering their childhood. From the conversation is easy to guess that Tanya is not indifferent to Kovrin and that she is bored with her father, who does not want to know anything but the garden, and turned her into a submissive helpmate. Kovrin also likes Tanya, he suggests that he can seriously get excited, but this thought rather makes laugh than he takes it seriously.
In the country he leads the same nervous life, as in the city: a lot of reading, writing, little sleep, often smoking and drinking wine. He is very impressionable. Once he tells Tanya the legend that he has either heard, or read, or seen in a dream. A thousand years ago, dressed in black a monk walked through the desert in Syria or Arabia. Just a few miles away fisherman saw another black monk - a mirage, which moved along the surface of the lake. Then he was seen in Africa, Spain, India, even in the Far North. Finally he came out of the limits of the earth's atmosphere and is now wandering in the universe, it may be seen on Mars or on some other star of the Southern Cross. The meaning of the legend is that a thousand years after the first appearance the monk should come back to earth, and now it's the time. After the conversation with Tanya Kovrin goes to the garden and suddenly sees the black monk, arising out of the vortex from earth to heaven. He flies past Kovrin, it seems that the monk softly and slyly smiles at him. Without trying to explain the strange phenomenon, Kovrin goes back into the house. He is covered with fun. He sings, dances, and everyone find that he has a special, inspired face.
In the evening of the same day Yegor Semenovich comes into the Kovrin’s room. He starts a conversation, from which it is clear that he wants to marry Tanya with Kovrin to be confident in the future of his industry. "If you and Tanya had a son, I would make a garderer of him." Tanya and father are often quarrelling. Comforting Tanya Kovrin understands that more close friends than her and Yegor Semenovich, he does not have in the whole world. Soon he was again visited by a black monk, and between them there is a conversation in which the monk explains that he exists only in the imagination of Kovrin. "You're one of the few who are justly called the chosen of God. You serve the eternal truth". All this is very pleasant for Kovrin to listen, but he fears that he is mentally ill. On this monk argues that all ingenious people are sick. "My friend, healthy and normal are only mediocre, gregarious people." Joyfully excited Kovrin meets Tanya and declares his love for her.
Preparations are underway for the wedding. Kovrin is working a lot, not noticing the commotion. He is happy. Once or twice a week, he meets with the monk and has long talks. He is convinced of his own genius. After the wedding, Tanya and Kovrin move to the city. One night Kovrin is visited black monk, they talk. Tanya finds her husband talking to an invisible companion. She's scared, like Yegor, who is on visit in their home. Tanya persuades Kovrin to be treated, he agrees in fear. He realizes that he became insane.
Kovrin is treated and has almost recovered. Together with Tanya they spend the summer in the village. He works a little, does not drink wine or smoke. He's bored. He quarrels with Tanya and accuses her that she made him to be treated. "I was going crazy, I had delusions of grandeur, but I was cheerful, alert and even happy, I was interesting and original ..."
He gets an independent chair. But on the day of the first lecture telegram informs that he cannot read because of the disease. Blood goes through his throat. He is not living with Tanya anymore, but with another woman, older for two years - Varvara Nikolaevna, who cares for him like after a child. They go to the Crimea and on the way stopped in Sevastopol. Yet at home, an hour before the departure, he received a letter from Tanya, but read it only in Sevastopol. Tanya informs about his father's death, accuses him of this death and curses. He is taken by possession of concerns, like fear. He clearly understands that he is a mediocrity. Enters to the balcony and sees the black monk. "Why do not you believe me? - He asked reproachfully, looking affectionately at Kovrin. - If you had believed me, then, that you were a genius, these two years you would have spent not so sad and poorly". Kovrin again believes he is chosen of God, the genius, not noticing that the blood comes from the throat. He calls for Tanya, falls and dies, his face is frozen with a blissful smile.