Reiji Takahashi works as a Special Operations Agent and while he was in the midst of investigating a criminal group's warehouse, he stumbles upon Nina. Nina was a victim of a child trafficking organization known as "Dolls" where they train young children to become assassins. Surprisingly, Nina herself is a skilled assassin who is now targeting Reiji's life. However, fate has something else in store as Reiji ends up being tasked with taking care of Nina. With no prior experience of raising children, can Reiji be a good father figure to this tiny assassin and teach her the ways of a normal life? Follow their heartwarming journey in this childcare comedy where a tough operative takes on the role of an adoptive father to a skilled assassin.
