Old miss Marple is on a train ride when she witnesses a murder in a passing train. She reports it to the police but they won't believe her: since no body can be found there can't have been any murder, right? As always, she begins her own investigation. The murder was committed while passing Ackenthorpe Hall and miss Marple gets herself a job there, mixing cleaning and cooking while searching the house for clues.而后，买单拿药，上上下下的跑，都是慕靖宇一个人包了。秦素素坐在注射室内安静的等着。再回来的时候，他已经有些气喘了。