Summer 2022. Jeanne, 9-years-old, spends her summer holidays with her grandfather Xavier in their family house. With no cell phone network or Internet, they are cut off from the world! The little city girl gets frustrated and depressed. Winter 1918. In the same house, another 9-years-old girl, Marie-Louise, is keeping her diary. Now imagine that Jeanne discovers the notebooks of her great-great-grandmother and projects herself to meet her in 1918. A deep complicity will be born between the two young girls separated by a century during a perilous rescue adventure.