The Sato family consists of their only daughter, Minami (Yurika Nakamura), her father, Toshio (Rutaro Koichi), and her mother, Shinobu (Sei Mahi). At first glance, the Sato family seems like a normal family, but they have a big secret that they cannot tell their neighbors. They are a pseudo-family with no blood ties, as Toshio is an intelligence operative, Shinobu is a sniper, and Minami is a skilled fighter who have infiltrated Japan as spies.
