第三位女郎 (1966)

《第三个单身女郎》（英语：Third Girl）是阿加莎·克里斯蒂所著的推理小说，1966年出版。

情节简介

年轻女孩诺玛·雷斯特里向侦探波洛求助，称自己可能犯下谋杀，随即又马上离去。波洛在侦探小说作家奥利薇夫人协助下展开调查，并亲自造访诺玛父母所住的横篱居。奥利薇夫人跟踪诺玛的男友大卫·贝克，却不慎被人打昏。在波洛的策划下，精神科医师约翰·史蒂佛林暂时照顾精神状态不稳定的诺玛。

依照波洛的调查所知，在诺玛5岁时，父亲安德鲁便抛弃了她和母亲葛蕾丝，跟另名女人露薏丝交往，最后离开英国前往非洲。诺玛与母亲同住，直到两年半前母亲去世。一年前，安德鲁带着新婚妻子玛丽回到英国，在家族企业工作。而诺玛则与克劳蒂亚·里斯–霍兰和法兰西丝·卡莉同租鲍罗登大楼的67号公寓。

奥利薇夫人曾探听出鲍罗登大楼的一名住户在不久前坠楼身亡，这名住户正巧是安德鲁过往的情妇露薏丝·查彭特。

诺玛离开了史蒂佛林医师的诊所，来到鲍罗登大楼的67号租屋与大卫·贝克见面。不久传出谋杀，诺玛被发现站在大卫的尸体旁。波洛与奥利薇夫人随警方来到现场，史蒂佛林医师指出诺玛不稳定的精神状态其实是吸食了毒品所致，让她产生幻觉及时间错乱。波洛随即揭露：安德鲁·雷斯特里实际上已死在非洲，其同事罗伯·奥韦尔假冒他的身份回到英国，以谋取雷斯特里家的财富，玛丽·雷斯特里与法兰西丝·卡莉其实也是同一人分饰两角的，他们设法用毒品控制诺玛。杀害可能会使他们的罪行曝光的露薏丝·查彭特和大卫·贝克，并嫁祸于诺玛。

改编作品

2008年，被改编为电视剧《大侦探波洛》第十一季第三集。故事背景从原著中的1960年代改成1930年代。

Third Girl is a mystery novel by the English writer Agatha Christie, first published in the UK by the Collins Crime Club in November 1966 and in the US by Dodd, Mead and Company the following year. The UK edition retailed at eighteen shillings (18/-) and the US edition at $4.50.

It features her Belgian detective Hercule Poirot and the recurring character Ariadne Oliver. The novel is notable for being the first in many years in which Poirot is present from beginning to end. It is uncommon in that the investigation includes discovering the first crime, which happens comparatively late in the novel.

Plot summary

Norma Restarick seeks help from Poirot, believing she may have committed murder. When she sees him in person, she flees, saying he is too old. He pursues the case finding that Ariadne Oliver sent Norma to him. He believes there is a murder that prompted Norma's fears. Poirot and Mrs Oliver gather information, visiting her parents’ home and her apartment building. Norma does not return home after a weekend visit to her father and stepmother. Mrs Oliver finds her in a café by chance with her boyfriend David. Poirot meets Norma at the café, where she mentions the death again. After describing the odd times where she cannot recall what has happened she leaves in fear again. Mrs Oliver trails David, ending up in the hospital after being coshed on the head upon leaving his art studio. Poirot arranges for psychiatrist Dr Stillingfleet to follow Norma; he pulls her to safety from a close call with speeding traffic and brings her to his place for treatment and for safety.

Norma's father Andrew abandoned her and her mother Grace when Norma was about 5 years old. Andrew had run off with a woman in a relationship that ended soon after. He travelled in Africa in financially successful ventures. Norma lived with her mother until Grace's death two and a half years before. Andrew returned to England after his brother Simon died a year earlier, to work in the family firm, arriving with a new young wife, Mary. Norma can recognise nothing familiar in this man, but accepts him. Norma is the third girl in her flat in the fashion of young women advertising for a third girl to share the rent. The main tenant, Claudia, is secretary to her newfound father; the other girl, Frances, travels often for the art gallery that employs her.

Mrs Oliver learns that a woman in the apartment building had recently died by falling from her window. A week passes before she tells Poirot, who feels this is what bothers Norma. The woman was Louise Charpentier. Norma says that her father ran off with Louise Birell. Later, Mrs Oliver finds a piece of paper linking Louise Charpentier to Andrew. Mary Restarick has been ill from poison in her food. Sir Roderick engages Poirot to find documents missing from his files which brings young Sonia under suspicion.