The average person has a lifespan of about eighty years in chronological order. This does not apply to Spanners. Some live their lives in reverse, some come to life for one day every ten years, and some like Dr. Adam Parr are immortal. When Dr. Parr discovers that his immortal brother Jonathan has somehow been murdered, he must use his old detective skills to solve the crime. To achieve this, he teams up with a short-lived, but quick-learning, mayfly and dives into the underworld. He must solve this crime, because if anyone can kill his immortal brother, Adam could just be next.