The architect Petros Ioannou rents a beautiful house in his attempt to alleviate as much as possible the sadness of his eight-year-old daughter, who recently lost her beloved mother in a car accident. Across from the balcony of the children's room, there is a low hill, insignificant, with two dubious little trees at its edges. The sensitivity of the little girl begins a secret communication with the "soul" of the hill, which develops quickly and ends in a friendship. The father of the little girl watches carefully and discreetly this strange event. At first, he attributes it to the usual fantasies of childhood. However, when they continue, he tries to solve the "mystery" and discovers a complex situation that will involve them all in a terrible adventure.