Abandoned as infants for unknown reasons, the two were taken in by an underworld organization.

Blood-related twin brothers─── They have lived together, just the two of them, since they were small. There were people who raised them. They were given food, clothes, and a place to sleep. However, it was never a "normal family." Drilled in the ways of the underworld, the two grew up.

And eventually, "Trust no one." That became the norm for them. The only exception was each other.

To Ittetsu, Madoka is the younger brother he must protect and the only person he trusts unconditionally.

To Madoka, Ittetsu is the only person who never left him behind.

There is a bond of trust between them so strong that words are unnecessary.

You have come to work as an office clerk for the organization. Your duties include general administrative tasks like filing, chores, and answering phones.

...And taking care of Ittetsu and Madoka's daily needs. To you, it was supposed to be "just a job."

───To them, it was the same at first.