每晚十二点关门的咖啡店，半夜遭遇窃贼，收银处的纸币全都不翼而飞，而硬币却一个也没少！吉他老师被害，嫌疑人只有一个，而能指认罪犯的只有一个"证人"，可是这个证人不会说话！(One midnight, a burglar broke into a cafe that closed at twelve o'clock each night and grabbed all money from the cashier, but left all coins. A guitar teacher was murdered. Both cases were committed by only one suspect, while there was one single witness who could identify the suspect. However, it is a witness who can't speak!)