Sachiko Suzuki is a female high school student. She claims that she is an alien and her mission on Earth is to conceive a child with a human man. Sachicko seduces her class teacher Mr. Fukuda. After their intimate encounter, Mr. Fukuda becomes becomes convinced that Sachiko is not a human. Meanwhile, female student Kobato Hagimoto knows that Mr. Murata has a crush on some male students. Because of this, Mr. Murata is treated as a pig by Kobata until he can't bear the situation anymore.

The body of Kazuyoshi Kawagishi, a construction company worker, is discovered stabbed to death in Shinjuku Central Park in Tokyo. Detective Masanao Ushio of Shinjuku West PD begins an investigation and finds that the murdered Kawagishi was an honest person who didn't have any troubles. Kawagishi worked for a company in Kofu City in Yamanashi, leaving behind his wife and daughter on Awaji Island in Hyogo. He seems to have started working as a laborer 3 years ago, having fallen on hard times when the company went bankrupt. Saeko Kawamura, Ushio's reporter friend, calls him wanting to talk about the case. According to Saeko, Kawagishi was one of the survivors of the "bus hijack arson case" that happened three years ago. In the bus hijack arson case, a man who was hallucinating under the influence of dangerous drugs set fire to an intercity bus going to Shinjuku and departing from Kofu Station...