Set against the backdrop of a summer on the French Riviera, the Roussier family navigates the severe disability of the youngest daughter, 13-year-old Bertille, while her older sister, 17-year-old Marion, seeks refuge in a relationship with an older boy.

In 1956 France, a priest is violently murdered, and Sister Irene begins to investigate. She once again comes face-to-face with a powerful evil.