In Tokyo, the reckless single mother Keiko moves to a small apartment with her twelve years old son Akira Fukushima and hidden in the luggage, his siblings Shigeru and Yuki. Kyoko, another sibling arrives later by train. The children have different fathers and do not have schooling, but they have a happy life with their mother. When Keiko finds a new boyfriend, she leaves the children alone, giving some money to Akira and assigning him to take care of his siblings. When the money finishes, Akira manages to find means to survive with the youngsters without power supply, gas or water at home, and with the landlord asking for the rental. 无人知晓的时间。事实。黑色的河流。西巢鸭弃婴事件。《无人知晓》花絮采访。几个月前看过，至今难忘。一个被美化的残酷故事依然残酷。阴翳里的明亮调子。真实事件完整版。《谁知赤子心》－－我来过，我很乖。 新搬来的公寓这家人是母亲惠子（You饰）带着四个孩子：明（柳乐优弥饰）、京子、茂、雪。但母亲却得对周围的人们撒谎说丈夫去海外工作，自己与长子两个人在一起生活。事实是其它三名弟妹是“黑孩子”，因为四个孩子有着各自不同的父亲。他们一直呆在家中，没有去学校上学。 在母亲去百货商店工作时，年纪尚小的明就在家中代替母亲行使家长的职责。突然有一天母亲不见了，她把手中仅有的20万日元现金和一张短短的便条留给了孩子们，把弟妹托付给明看管后，就悄然地离家出走。 无亲无故，对外面几乎一无所知的四个孩子们，要开始面对新的生活，那实在不是件容易的事情……
