Based on

Movies like Wild Roots of Love (1960)

Four little girls flee the cold concrete world of the housing project they live in, take refuge every evening in a house on an island in the middle of the Marne River. It is secret hideaway that no one should trespass. Unfortunately a big girl reveals everything to the schoolmistress and scandal breaks out. But it is Sophie, the youngest of the group, who gets suspected by her..."friends".