In August 1939 Vincent Degraël, a young teacher from Paris, goes to Le Havre to stay for a few days with his colleague Denis Borade and his parents. But the day before his departure he picks up a book from Borade's parents' library that has such an effect on him that he retires to the bedroom to read it. It's called Le voyage d'Hiver, by Hugo Vernier, a writer unknown to him.
The book is thin and divided into two parts. The first part is about a fifth of the total length, and concerns a man who is ferried to a small island on a lake, where an elderly couple lead him to a bedroom in a building, where a meal is laid out on a table for him, and where he begins to eat alone. Then the second part begins, which is a long declaration interspersed with poems, enigmatic sayings and blasphemous incantations. The effect it has on him is profound, and this is just one sentence:
'Hardly had he begun to read than Vincent Degraël felt an unease which was impossible to define precisely, but which grew in proportion as he turned the pages of the book with an increasingly trembling hand: it was as if the sentences before his eyes were suddenly becoming more familiar to him, were irresistibly reminding him of something, as if the reading of each was imposing, or rather was superimposing, the memory - at once precise and vague - of a sentence which must have been almost identical and which he must have read elsewhere; as if these words, more tender than caresses and more perfidious than poisons, alternately transparent and opaque, obscene and warm, dazzling, labyrinthine, and incessantly oscillating like a maddened compass needle between a hallucinatory violence and a fabulous serenity, were sketching out a confused configuration in which there seemed to be a hotchpotch of Germain Nouveau and Tristan Corbière, Villiers and Banville, Rimbaud and Verhaeren, Charles Cros and Léon Bloy.'
Degraël begins to recognise a large number of quotations from late 19th century poets, but is stunned to discover that the book was published in 1864 - before any of the quoted poets had been published. Searching his friend's parents' library, he can find no reference to Vernier. With the help of his friend, they find nearly 350 quotations from nearly 30 authors - or rather, which have been attributed to those authors, as it seems clear that they have been directly borrowing from Le voyage d'hiver: the implications are enormous. The war intervenes, and Degraël is unable to continue his research apart from verifying at the British Museum that there was no printing error, and the book was in fact published in 1864.
Back in Paris after the war he continues his research and finds frequent references to Vernier in original diaries and letters of poets, even discovering that the famous 'Je est un autre' ('I is another') of Rimbaud, and Lautréamont's 'La poésie doit être faite par tous. Non par un.' ('Poetry must be made by all. Not by one') originate from the pen of Vernier.
Alas, he cannot get his hands on a copy of Vernier's book: Borade's parents' house was destroyed during the Le Havre bombing, the Bibliothèque nationale de France lost its copy on the way to the bindery, and not another copy can be found anywhere after searches in hundreds of libraries, archives, and bookshops. He concludes that the poets themselves must have destroyed the other copies of the single print run of 500. Apart from discovering that Vernier was born in Vimy (Pas de Calais) on 3 September 1836, nothing more can be learned.
After 30 years of searching in vain for proof of the existence of Vernier and of his work, Degraël dies in the psychiatric hospital in Verrières (where Stendhal's Le rouge et le noir (The Red and the Black) begins). His former students undertake to gather his huge pile of documents and manuscripts. Among them, they find a book carefully inscribed Le voyage d'hiver: its first eight pages tell of the fruitless searches Degraël made, and the remaining 392 pages are blank.