Kabukichou, located on the east side of Shinjuku ward, is a bustling hub of chaos illuminated by colorful neon lights, yet shrouded in darkness. John H. Watson, employed at a university hospital on the opposite end of town, seeks assistance with a peculiar case. His search leads him to the underground bar, Pipe Cat, a popular meeting spot for Shinjuku's top detectives, including the infamous Sherlock Holmes. Upon meeting the eccentric investigators and learning of their pursuit of Jack the Ripper, John agrees to drive Sherlock to a crime scene related to his own case. What he witnesses there proves Sherlock's unmatched detective skills but also reveals his peculiar quirks. As John continues soliciting Sherlock's help, he becomes enmeshed in the exhilarating lifestyle of solving cases beyond the grasp of ordinary minds. Along the way, he uncovers the true colors of Kabukichou and solves the unsettling mystery surrounding his case.