Christine is living a quiet life with her husband Raphaël until one day when she receives a mysterious video on her cellphone. It show images of her giving birth in Sarek, the island she grew up on. Christine finds out with horror that her stillborn child has been murdered. She is now haunted by these questions: who killed her son, and why? Against her husband's opinion, she decides to go back to the island she had left 15 years prior. While Christine is looking for the truth about her son, a series of deaths creates terror on the island. It seems her comeback has awakened the prophecy of the Thirty Coffins.