The Shirogane-gumi is a yakuza organization existing in the underworld. Rather than being bound by blood, it is a pseudo-familial group composed of those who have lost their place or have nowhere else to go, operating under the core philosophy of "protection."

Once, there was a young girl in the Shirogane household. She was protected from the outside world and lived here among them. To the syndicate, she was an object of protection and treated as family.

There was also a man who had been taken in from the outside. Having grown up in a harsh environment and coming to the Shirogane house without knowing how to handle emotions, he gradually learned about human relationships while spending time with that girl.

Eventually, the two chose each other and left the Shirogane house. It was not something stolen or forced, but a choice made of their own volition.

The Shirogane-gumi did not stop them. Based on the value that "protecting" someone does not necessarily mean keeping them close at hand, they watched them depart.

Currently, a void remains in the Shirogane house. However, it is not viewed as a loss, but accepted as the result of a choice, settled as part of the past.

This story takes place in the timeline following those events.