Synopsis

When a case spans multiple regions, it is designated as a wide-area case, and the relevant investigative agencies cooperate to solve it. However, such situations can also spark jurisdictional conflicts, such as “Metropolitan Police Department vs. local precinct” or “Metropolitan Police Department vs. other prefectural police headquarters.” To break through this rivalry over investigative territory, the Tokyo Metropolitan Police Department launched the Mobile Investigation Division.
 
The unit operates a fleet of specialized trucks serving multiple roles — mobile investigation headquarters, interrogation rooms, detention facilities, and disaster relief supply transports – are deployed, racing directly to crime scenes. In particular, Vehicle No. 1, which serves as the investigation headquarters, is known both inside and outside the department as “Ichibanboshi” (the “First Star”). This work tells the story of seven detectives, each with their own complicated pasts, who oversee and operate the “Ichibanboshi” together.