In a small mountain community, two local people - Camille, a teenager, and Simon - who both died years earlier, suddenly re-appear at their homes. They have not aged, and they are completely unaware of their own deaths. Camille and Simon assume they can rejoin the world of the living as though nothing has happened, but their return throws their friends and family into a state of turmoil.

Simon approaches Adèle, but Thomas finds out about his 'return'. In the meantime, Camille is unable to fit back into her family again. Her mother Claire and father Jérome separated after her death, and now Claire is in a relationship with Pierre, an odd but charismatic figure who knew all along that the dead would return.

Determined to come out of hiding and return to something resembling normal life, Camille invents a new identity for herself as 'cousin Alice'. Her sister Léna finds a strange, fast-spreading scar on her own body. Simon gets closer to Adèle, who finally accepts he has returned and is not a manifestation of her grief. But as the dead try to reclaim their lives, for the living, things seem more and more disturbed.

Camille's new identity as Alice is going well, but Léna's scar is growing and seemingly draining her of energy. Léna is convinced that Camille is behind it and publicly denounces her to their friends. Julie can no longer keep Victor under wraps and the police take him away. Adèle gets back with Simon and introduces him to their daughter, Chloe... but then discovers the true circumstances surrounding his death.

The dead gradually come out into the open but are unable to resume their normal lives. Camille is rejected by Frédéric, and Simon is abruptly separated from Adèle and Chloe when Thomas shoots at him in self-defence. Victor wanders around, looking for his murderer, while Julie begins to have doubts: could she be dead too?

In the city without electricity Pierre forms a community around Camille, who is now regarded as a kind of 'prophet'. Julie finds refuge with Laura and Victor, whose body is undergoing a strange transformation. Meanwhile, Léna grows closer to Serge but has to escape back to the town.