A dad had young daughter named Blythe who drowned in pool

Poland, 1945. Mathilde, a young French Red Cross doctor, is on a mission to help the war survivors. When a nun seeks for her help, she is brought to a convent where several pregnant sisters are hiding, unable to reconcile their faith with their pregnancy. Mathilde becomes their only hope.

Four children become friends during the summer holidays, and out of sight of the adults they discover they have hidden powers. While exploring their newfound abilities in the nearby forests and playgrounds, their innocent play takes a dark turn and strange things begin to happen.