The plot is quite straightforward: a middle-aged man, Léon Delmont, takes the train from Paris to Rome to visit his lover, Cécile, whom he has not informed of his arrival.

He now intends to tell her that he has finally decided to leave his wife, found a job for her (Cécile) in Paris and is ready to take her back there and live with her.

The entire action takes place in less than 24 hours and never leaves the train in which the main character is travelling, except during the flashbacks.

For instance, as the train passes the Fontainebleau Forest, the main character sees the "Grand Veneur", a ghost rider that is rumoured to haunt it and ask questions to the persons he comes across.

All these surreal episodes culminate in a nightmare in which the main character is judged and condemned by the decayed corpses of the old Roman Emperors and the pagan gods who deem him unworthy and deny him entry to the city.

In this respect, it is significant that, in several of the story's flashbacks, the main character is reading the Letters of Julian the Apostate, the emperor who rejected Christianity and sought to restore traditional polytheism.

However, Butor's extremely detailed and careful analysis of the slow, almost mechanical workings of doubt and fear make his eventual change of mind absolutely inevitable.