BLUE, the world's top detective training school, once produced a genius with outstanding talents and a bright future. However, he had a fatal flaw as a detective, which caused him to be kicked out of BLUE and banned from continuing to be a detective.Five years later, a detective from the Metropolitan Police Department's Investigation Section 1, the simple fool Isshiki Tatsumaru, came to find Ron, who lived a frustrated and boring life every day, and asked him to help investigate the serial murder case, letting Ron's originally static time go.Turn again.After calling him “Dudu”, he felt that there were infinite possibilities for the two of them to work on the case together, so he named him %Dudu as his partner.Nun, who is responsible for solving the mystery, and Dudu, who is responsible for investigating the case, are detective partners with completely different personalities, and they begin to solve the mysterious case brilliantly.