William is in the heat of a hostage situation at a high-end department store. Helena, a young girl he's with, has the gift of synesthesia, which allows her to "see the color of people's voices"...!? The name of the criminal gang's leader is Jake Voorhees. When Jake, who is both intelligent and dangerous, reveals his outrageous plan, the "flame" hidden within William's chest flares up!! The key to this case lies within the "voice"――.[1]