In a French thermal town, a man is found poisoned. His ex-girlfriend is arrested for the murder but her estranged cop daughter tries to prove her innocence which leads her much further than she could have ever imagined.

Several notables from the Chamonix region are found murdered in their homes. To move forward with investigation, police captain Thomas Delhaye decides to release Juliette Hémon from prison, imprisoned for a strangely similar case.

On a winter night in a ski resort in the French Alps, Mona, a young Italian seasonal worker, has locked herself out. She is struggling in the cold while looking for shelter. Her nighttime journey takes her near an unknown presence.