Édouard (Édouard Sulpice) is a BlaBlaCar driver in his mother's car, and supposed to be picking up two women to drop off at Die (Drôme) before going to his mother's. But he's very surprised, in fact annoyed, when two guys appear (and very late at that): Félix (Éric Nantchouang), who's on his way, he believes, to give a pleasant surprise to a young woman he danced with and spent an innocent night with on the banks of the Seine, Alma (Asma Messaoudene), who took the train earlier in the day to Die, where her parents have a house they spend the summer in; and Félix's best friend Chérif (Salif Cissé).
Félix works as a homehelp to the elderly, and Chérif has rather clumsily taken a week's leave from his job in a small supermarket. The pair are very different from each other: Félix is black, hot-tempered, handsome, tall and slim, whereas Chérif (also black) is very calm, quite chubby, and a fair bit smaller – in fact, he's far removed from the neurotypical, as he seems to have an unusually large knowledge for someone of his poor education and job status, he prefers to read literary classics rather than his cellphone, and he avoids sports activities, saying he has otitis.
The three don't get on well at first. Félix makes fun of Édouard for his mother phoning him and calling him 'chaton' ('kitten'), and Édouard objects to him eating crisps in his mother's car. When they stop off at a motorway aire, Édouard shouts at them for talking amongst themselves and ignoring him, saying this isn't the etiquette of co-voiturage. He's even more annoyed when he's persuaded by Félix into having a look at the town before taking them to the campsite, and he reverses into a heavy object in a narrow street and makes it with difficulty to the campsite to afterwards learn at the garage that it will take 'une grosse semaine' ('at least a week') for parts to come for the wheel bearing to be fixed.
So Édouard is forced to sleep in the same tent as the snoring Chérif, although the two learn to relate to each other in the multi-lingual campsite also inhabited by the English and the strongly Francophile Dutch. And as Édouard and Chérif (who don't have partners at home) watch the mild loveplay of Félix and Alma in the river, Chérif concludes that they are both 'galériens' ('losers': the Americanised sub-titling translates this as 'washouts'!)
Although this modernised Rohmerian tale is essentially a light psychological study in diversity, showing how (often very different) people can come together, jump in and join (the title À L’Abordage isn't for nothing), it also highlights how arguments can come close to the surface, often caused indirectly by unrelated psychological trauma: examples of this are the fight during the canyoning episode, or Félix – who has just split up with Alma largely because his inappropriate, over-enthusiastic behaviour turns her off – suggests that Chérif is gay because he passes so much of his time with unavailable women. And this comment in turn has a knock-on effect with Chérif, who turns down the suggestion by Héléna (Ana Blagojevic) that he look after her baby Nina for two hours while she has a massage to relieve her tension.
Chérif's obviously disinterested attentions to Nina have been an example of his difference: while the others have played sports or love/sex games, he's spent much of his time as a casual babysitter, a substitute father as Héléna's partner – whom she only once mentions (and only as 'il') has been called away. Furthermore, this relationship between Chérif and Héléna is another example of the meeting of different classes, although they have a geographical similarity: Chérif comes from La Courneuve, Héléna grew up in adjoining Stains and they both remember the same supermarkets.
Towards the end there's a scene in which Chérif and Héléna, having left the rather weird staff member Nicolas (Nicolas Pietri) – who is now off duty with a sprained arm, is terrified of the end of the world, and whom Alma sees as a slit-your-throat pessimist – in charge of Nina while they go to the camp bar for a drink. They're met by Édouard, who invites Chérif to sing karaoke, but he's shyly very reluctant until everyone in the bar joins in chanting 'Chérif!' and Héléna encourages him to join her in singing: à l'abordage! Héléna chooses 'Aline', a 1965 summer hit by Christophe, which is appropriate because it's about sand, beach and lost love (although Félix is absent).
In the morning we find Chérif and Héléna staring lovingly at each other in bed naked, Édouard cleaning the shower block mirror as he's changed places with Nicolas and needs money for car repairs, and Félix being lulled awake by a young woman playing the guitar and singing: she turns out to the clown the trio saw amusing kids when they went on a visit to Die. A delightful film.