Henri had thought of everything before leaving on holiday: a newly serviced car, the shortest itinerary possible and the right time to depart in order to get to destination "before night fall". He is driving on the highway with his family, but unexpected delays had lowered his average speed. So, when he finally exits a traffic jam, Henri accelerates to 150 kms/h to make up for lost time. After a turn in the road, he collides with a car stuck in traffic. Families are shattered.

The first part of the film is shot at actual speed, but when the shock happens, it switches to extreme slow motion. Friends and relatives of road crash victims appear. They are at the heart of the accident. They are seen floating, almost unreal, like flying over the tragedy scene in the same dynamic as the drivers themselves. They are impacted by the shockwave.