An octopus with eyes whose retinas lie in front of the optic nerves is mysteriously murdered. At the crime scene, "I" recall how I met, came to know, and fell in love with the octopus. The police gradually begin investigating, gathering evidence and checking suspects, but with insufficient evidence, the case is temporarily ruled a suicide. Ten years later, a breakthrough is made in the study of the octopus's eyes: they can distinguish a wider range of frequencies than the human eye. With special glasses and a brain-computer interface helmet, the octopus's posthumous work reveals scenes invisible to the naked eye. It also gives the police an idea of how the crime was committed, allowing them to trick the killer into giving themselves away. After finishing the story, look back at the memories and you'll realize the entire crime was already laid out in scattered pieces.