小山田响子（松井玲奈 饰）辞去了演员工作，离开东京，回到故乡福冈，却遭到她同父异母的妹妹本桥菜穂子的暗中跟踪。某日，菜穂子装作偶然与响子接触，从响子的记事本中获取了她们的另一个同父异母的妹妹小暮杏奈的信息，并和杏奈电话联系…有的定居都市，有的住在森林中，从小未曾相见的三姐妹，轨迹如同叶脉交叉相连，喧嚣低语，最终，她们的天性（saga）跨越了血缘和命运，交响和鸣。

28-year-old Kyoko return to her hometown of Ureshino in Saga Prefecture from Tokyo after a stint as an actress. It is here that she “runs” into Nahoko, her half-sister. Nahoko is secretly stalking Kyoko. Things get a lot more complicated when another half-sister is revealed.