Raphael is an ex-boxing champ who now trains his young brother Manu. Tony, Raphael's ex-rival, returns to town to wed his reluctant fiance Chinh. As soon as Chinh and Raphael meet, sparks fly, and soon the two are sneaking out together.

Oscar, Simon, and Aïssa, three childhood friends, go to Paris to celebrate some good news. But on the night bus taking them home—the N121—an exchange between passengers spirals out of control, and the situation quickly goes off the rails.