Hidden in Rome, King Arthur is planning his return to oppose the army of his former friend Lancelot.

On this summer day in 1977, Léon and Eugénie are preparing to welcome their entire family into their small house. It's their grandson Stéphane's birthday, but it's mostly a pretext to gather with the patriarch, weakened by illness. But what appears to be a routine family reunion will highlight everyone's tensions and resentment. It reaches a point of no return.