Forty-year-old detective Eiji Kirisame has found maybe the strangest witness of his life: a silent high school girl named Tsugumi Kuchinashi who was at the scene of the crime. Her statements mostly consist of shoddy doodles on a drawing pad, but Eiji is no stranger to piecing together the truth from limited evidence--and besides, it seems like Tsugumi might have a knack for deduction! So he'll take every page seriously if it might help solve the case. But, uh, does that last page really say..."Marry me?"?!