At a pharmaceutical plant, Banba and Kimura talk while descending into a large underground lab. They speak of the origin of the shadow monsters, created by ancient warring tribes to bring peace. The first monster destroyed the two originating tribes. Though it is now gone, its cells remain, infecting animals of all sorts in the modern world. These infected animal become new monsters dubbed Kagewani. In the lab the two men see a newly-produced clone shadow monster, an offspring from the sewer monster seen before, and the part-plant young man from an earlier episode. The escaping sewer monster gores Banba, frightening Kimura into running alone into the lab's safety cell.
Rescuers cut into the lab's safety cell, releasing Kimura unharmed. Banba has survived. though surveillance video shows the shadow monster clone entering Banba's old scar. In the operating room, a shadow monster grows out of Banba. Kimura orders his capture, but when the team arrives the medical staff are dead and Banba is gone. Banba confronts Kimura in the underground lab, attacks him using the shadow monster within him, and leaves the facility. He meets the woman with the shotgun from earlier episodes, now aged. She warns him she will kill him when the Kagewani takes him over. He walks away into the city.