 Michael works at a nursing home and is growing tired of people who neglect to care for their elderly relatives. He reads a book by Simon Vale about the Zodiac killer which inspires him to go on a killing spree. Michael claims Zodiac s title, targeting those who mistreat the elderly. The only person who suspects Michael is Simon Vale, who plans to use Michael s scheme as the subject for the latest revision of his book on the Zodiac killings.