Beneath the Hoho Museum lies a door that will no longer open—the Wan Koro Police capture an intruder, but the culprit is whisked away in a suspicious vehicle. Behind the incident is the evil genius, Professor Shiriarty. His target is the mysterious treasure, the "O-Parts." To capture Shiriarty, a ruthless criminal who will stop at nothing to achieve his goals, Detective Butt teams up with Audrey, who has come from the international police force, WANTEDPOL. Detective Butt puts his reasoning to work on the baffling cases that occur one after another. Meanwhile, Shiriarty unleashes an incident that shakes the town. "Darkness shall extinguish the light. With the power of these O-Parts." Who will win—Butt or Shiri? Can they protect the mysterious treasure from the hands of evil!?