The president from the Republic of Poliador arrives in Japan, and the Modern Crime Prevention Task Force are assigned to assist the First Investigation Division in protecting the embassy from the outside as security personnel. Daisuke is invited inside the embassy as a representative of the Kambe Group. After the dead body of an embassy employee is discovered inside the building, the president and Daisuke are forced to evacuate to the panic room. Daisuke traces the footsteps of the suspected killer by hacking into the surveillance cameras. Kato finds the suspect as he attempts escape and tries to apprehend him.

After escaping from the cargo ship, Daisuke and Kambe pursue Shigemaru and arrive at the old site of the 3rd Laboratory owned by the Kambe group, which is the source of all the mysteries. Daisuke confronts Kikuko, the head of the family, with his burning questions, but her answers force him to make a crucial decision. The truth behind the tension and conflict between the three generations of the Kambe family becomes clear.