Retired assassin Taro Sakamoto wants his neighborhood shopping arcade to be as safe and peaceful as the family life he built after leaving the underworld. When shoplifting, gangs, sabotage, and other local trouble threaten the businesses around him, Sakamoto and Shin quietly step in while trying to keep the danger away from Hana and the rest of the family. The spin-off turns their exceptional skills toward small-town problems and the mission of making the arcade a better place to live.