Arthur is a history teacher who lives alone in Paris after having broken up with Claire. He is a sensitive man, full of existential doubts and questions. He has to go to Lisbon to meet an eminent historian whose work is the subject of his thesis. Having just made up with Claire, he decides to take her along. She's an ideal travel companion and it seems their relationship has not yet exhausted its potential. But moving from Lisbon to Oporto, their fantasy of a second honeymoon clashes with the reality of a world on the verge of a nightmare.

Arthur, professeur angoissé, se décide à faire le voyage jusqu'au Portugal pour rencontrer l'éminent historien à l'origine de sa thèse. Claire, son ex-compagne, qu'il vient de revoir, l'accompagne.