Six months after the flooding of the valley much of the town’s population have left, though some remain hoping to find loved ones taken by The Horde. Still pregnant with Simon’s baby, Adèle faints and is taken to hospital, where the staff decide to induce labour. Richard Berg, an expert tasked with finding the causes of the flood, encounters Toni.
The Returned have been hiding out for months in a zone rendered inaccessible by the flooding. They are still holding Julie, Victor, Camille and Claire, who have grown used to their life as refugees amongst them, but two of Camille’s classmates are about to cause problems..
Since the return of Victor’s mother, Julie feels out of place and she decides to leave the Domaine. Camille grows closer to Virgil, a mysterious young Returnee, which is not to her mother’s liking. Adèle begins to get used to her baby, and Berg thinks that he may have found the reason for the flood.
Julie visits Victor’s former home where a neighbor tells her why his family was massacred. Berg and Jérôme also visit Victor’s hamlet and find his old drawings. Léna is reunited with her mother and sister. After the disappearance of her baby, Adèle comes under suspicion from the police.
Jérôme and Berg take in Audrey, who has managed to escape to the town from the Domaine. Simon tells Adèle that they need to get their baby to safety away from The Returned. Victor senses that Julie is in imminent danger so decides to leave the Domain – accompanied by Madame Costa.
Sandrine has handed her daughter Audrey over to Pierre’s men, who keep her in the cellar. Having taken refuge in the church, Adèle and Simon start to grow closer. Jérôme and Berg try to reach the Domaine via a roundabout route. Julie has found Victor’s father, who is now an old man in a coma holding a dark secret.
Jérôme has joined his wife and daughters in the Domaine, but the Returned prevent them from leaving. Lucy and the Horde are on the move again, while Julie goes to the Helping Hand to find Victor. The army lower the water level and plan to re-integrate the Domaine with the rest of town, which would force The Returned into exile.
Camille understands that she can’t stay with her loved ones any longer and must go back to the Returned. The Horde have dispersed but Lucy doubts that they can now return to where they came from.