A couple buy a beautiful home in an upper-class neighbourhood where a murder-suicide occurred. However, when strange events begin to happen, they soon suspect their new neighbour may have played a part in the killings.
一名代号 13 的杀手在一次任务中险些失手，之后她被自己所属的组织“阴影”所停职。在一段时间后，这位杀手遇到了Monji，一个不幸失去母亲的小男孩。在Monji意外失踪后这位杀手开始了寻找Monji的路途，她甚至不惜对抗她所属的组织。
