American novelist Tom Ricks (Ethan Hawke) arrives in Paris determined to renew a relationship with his estranged young daughter, Chloé (Julie Papillon), whom he is desperate to see. When the longed-for meeting goes poorly — he flees after his wife Nathalie (Delphine Chuillot) notifies the police that he has violated a restraining order—he ends up in a seedy hostel on the outskirts of the city. Unable to pay for his room and board, he agrees to work as a night guard at a warehouse for the dubious proprietor, Sezer (Samir Guesmin), though he has no idea what the vaguely criminal types who access the building at odd hours are doing there, or what, if anything, they might be hiding. Locked in a basement room with a bank of monitors, he spends the hours writing elaborate, imaginative letters to Chloé that center around a mystical forest, and later makes an unwise attempt to visit her at the schoolyard.

Something of a curiosity back at Sezer’s café, Tom elicits the sympathy and amorous attention of Ania (Joanna Kulig), a Polish barmaid with an interest in poetry, and has unpleasant run-ins with his menacing, openly hostile hallmate, Omar (Mamadou Minté). Then one evening, invited to a posh literary gathering by an Englishlanguage bookseller who recognizes him from a dust-jacket photo, Tom meets Margit (Kristin Scott Thomas), an enigmatic translator whose magnetic presence and
worldly manner intrigue the down-and-out author, more starved for love and comfort than sophisticated company. She seduces him, haughtily dictating the time and place of their rendezvous in the Fifth Arrondissement. Margit’s muse-like influence on Tom only deepens as she boldly encourages him to abandon all other priorities, including family, and focus on novel writing. But their passionate affair coincides with a string of inexplicable events—a murder, a disappearance—and slowly Tom’s anxieties and inner torments begin to derange his sense of what’s real…