César Casalonga wins a France presidential election primary for his party. But that victory was rigged. Helped by Paul Francoeur and Marylin, before the press or his opponents find out, César Casalonga must disentangle the conspiracy.

Les lendemains de veille tells the story of Vincent, Malo, Lola, Matéo, Blaise and Xavier. At the time they were young and had a dream, that of living together; free and autonomous. And this dream had a name: "The community of the days before." However, their group ended up doing like everyone else and they gradually lost sight of each other. They hadn't made a date in the future, but the death of one of their own decided otherwise.

Alexandre, a somewhat lost thirty-something, decides to start out in the professional world. Loris, his misanthropic roommate, works on a universal method to succeed in life, and Patrick, Alexandre's father, decides to stop his chemotherapy. Everything is on track, until Manon shows up in their lives.