The wife of a manager at one of the pharmaceutical companies in Austin, Texas, Robert Black, was brutally murdered in a house in Windsor Hills. Her husband Robert Black becomes a suspect in Eva's murder. While Bleck is awaiting execution in the prison in Huntsville, Texas, the policeman who was in charge of Bleck's case is approached by a stranger who introduces himself as a botanist. He had only recently completed experiments with indoor flowers and received amazing results proving that plants have memory and, at the moment of experiencing psychological events, they imprint the criminal in their language, fix it, and remember the suffering of the victim. He invites the policeman to conduct an unusual experiment in the Blacks' house in order to establish a portrait of the real killer...