Professional assassins Kazuki Kurusu and Rei Suwa live together, fleeing memories of their grim childhoods and avoiding emotional connections. When their mission goes awry and they end up bringing Miri home, there is only one reasonable thing to do: return Miri to her mother. But the girl's innocent laugh and pure worldview quickly enamour her to Kazuki, who secretly enjoys playing a parent, and it is not long before Rei's impenetrable heart makes room for Miri.
