A vn based on the characters from the riichi mahjong client Mahjong Soul.

During an investigation of Mahjong Crimes, mystery sweeps up an unsuspecting officer as the guests of the shrine finds him dead. MCD (Mahjong Crimes Division) officer Watson calls his niece Keikumusume, an avid fan of mystery stories, to come and solve this bizarre murder. She might not know much about mahjong, but will her knack of tinkering with the fragments of clues and lies be the key to finding the murderer?