How Long Is “Dans La Nuit”?

An un-named author is driving to meet her agent late one night. In the middle of an unlit country road she accidentally hits a young cyclist but fortunately the boy seems uninjured apart from a mysterious mark on his back. Though she can’t prise a word out of him she finds his address in his bag and drives him home to an isolated farmhouse. The boy’s slight unnerving parents are surprisingly unconcerned about their son, who is swiftly locked in his room, but they invite their guest in and offer her a glass of wine. It turns out the father is also a writer, but the manuscript he proffers is merely a single phrase repeated dozens of times on each page. Something very odd is going on...