Shinichi Kudou finds himself caught in a peculiar mystery involving a strange wall and an unexpectedly crucial black Labrador. What begins as a straightforward case quickly spirals into something far more complex, testing the young detective's observational skills against a puzzle that refuses to reveal its secrets through conventional means. The black Lab becomes an unexpected partner in solving the crime, its behavior and movements providing clues that human witnesses have overlooked. Shinichi must bridge the gap between what he can deduce logically and what the animal is trying to communicate, forcing him to approach detective work from an entirely new angle. Blending comedy with genuine mystery, the OVA maintains the series' signature charm while delivering the intellectual satisfaction fans crave. Shinichi's wit sharpens against this offbeat case, and the interactions between detective and dog create moments of levity that contrast with the darker puzzle at hand. Perfect for those who enjoy mysteries with unexpected twists and a touch of humor, this compact story proves that solutions sometimes come from the most unlikely sources.