Poirot pays what appears to be a routine visit to Dr. Morley, his dentist, but shortly after he leaves the clinic, the doctor is found dead with a gunshot wound to his temple, an apparent suicide. Poirot suspects foul play, and all those who entered the doctor's offices after Poirot left are suspect. They include Alaistair Blunt, a prominent and very influential bank director, Frank Carter, a young fascist thug with a personal grudge against Morley, Mr. Amberiotis, an enigmatic recent arrival from India suffering from a toothache, and Mabelle Sainsbury-Seale, a charity worker also recently returned from India. When Amberiotis is found dead in his hotel room from an overdose of Novocaine and Sainsbury-Seale disappears, Poirot rightly expands his list of suspects and connects the crime to events that occurred in India 12 years earlier.
波洛(大卫·苏切 David Suchet 饰)在拍卖会上看中了一面非常精美的镜子,哪知道这面镜子却被名为杰维斯的艺术品经销商给高价买走了,不仅如此,杰维斯还聘请了波洛到他的府上,去调查他手底下的一名建筑设计师。
杰维斯太太(艾玛·菲尔丁 Emma Fielding 饰)是一个神神叨叨的女人,她坚信丈夫买回家的镜子上禁锢了邪恶的力量,会有人因为这面镜子而丧生。让大家没有想到的是,杰维斯太太的预言很快就得到了应验,当晚,杰维斯先生被人发现死在了书房里,房间里的一切线索都显示杰维斯先生是自杀,但聪敏的波洛很快就从中发现了疑点。