They are the illegitimate children of a certain family, in recent years they have relied on each other to live. But once, they met an older woman who had been to prison for a shocking case with a series of victims. Meet and get to know a serial killer.

Now, they live with that woman in an apartment. She acts as their guardian, gives them pocket money, gives them a normal environment at home.

Ran: "Mei, where's my shirt?"

Rindou: "I can't find it either!"