The DarkZide stealthily appeared on Earth from their dying world in Dark Dimension to acquire the Larmu, human life-energy, to continue their existence. To counter the threat, Takeshi Munakata of the Cabinet Secret Service established the group S.A.I.D.O.C to intercept the DarkZide. S.A.I.D.O.C developed the Crystal Power needed to completed the Changérion project. However, the power was accidentally transferred into the body of detective Akira Suzumura.
Space Investigator Justy arrives on Earth in pursuit of a dangerous bio-weapon, Debora, which has the ability to attach to living things and to control their consciousness and pass on to others through bodily contact. The only way to capture Debora is with a kiss, so Justy commandeers the body of a young man, Masayoshi, and has him kiss any person she suspects of being possessed by Debora.
While returning from a business trip to Hokkaido, Detective Kamei of the MPD greets a middle-aged traveler in the waiting room of Minami-Wakkanai Station but is ignored by him. On the limited express to Asahikawa, the same man happens to entrust Kamei with a floppy disk before dying. The floppy contains his investigative notes on a murder that happened two years ago...
