Curtain was first published in 1975, but it was written in the 1940s during the Second World War. Agatha Christie had written it with the intention that it be published after her death, but in 1975 her publishers persuaded her to release it so that it could appear in time for the Christmas season – a ‘Christie for Christmas’.

In this book Poirot and Hastings have come full circle, returning to Styles, the scene of their first case. Poirot is now an old man (just how old is not revealed  – I think if you go by the chronology of the novels he must have been about 120, but there is no need to be too precise), and close to death.  Hastings is the narrator of this mystery. He is saddened by the devastation age has had on Poirot:

My poor friend. I have described him many times. Now to convey to you the difference. Crippled with arthritis, he propelled himself about in a wheeled chair. His once plump frame had fallen in. He was a thin little man now. His face was lined and wrinkled. His moustache and hair, it is true, were still of a jet black colour, but candidly, though I would not for the world have hurt his feeling by saying so to him, this was a mistake. There comes a moment when hair dye is only too painfully obvious. There had been a time when I had been surprised to learn that the blackness of Poirot’s hair came out of a bottle. but now the theatricality was apparent and merely created the impression that he wore a wig and had adorned his upper lip to amuse the children!

Only his eyes were the same as ever, shrewd and twinkling, and now – yes, undoubtedly – softened with emotion. (pages 12-13)

Curtain is in many ways a sad book. Sad because this is Poirot’s last case and he dies, with  X, the murderer, apparently having got away with his crimes. Sad, too because Hastings is in a nostalgic and morbid frame of mind, mourning the death of his wife and wishing himself back into happier times. It doesn’t help him that one of his children, Judith, a secretive child now aged 21, is also staying at Styles, the assistant to Dr Franklin who is engaged in research work connected with tropical disease. She resents her father’s interference in her life and is scornful of what she considers his sentimental and old fashioned ideas. Sad too, because of the setting. Styles, once a well-kept country house has been sold  and is now being run as a guest house, the drive badly kept and overgrown with weeds and the house iself badly needing a coat of paint.

But is also an interesting puzzle. Poirot knows the identity of X, a murderer who is present at Styles but will not tell Hastings, because Hastings would not be able to conceal his knowledge – his face would give him away. Poirot is convinced that X will kill again, but he doesn’t know who the victim will be. He asks Hastings to be his eyes and ears whilst he is confined to his wheelchair. He also gives Hastings newspaper cuttings of five murder cases, all of which were committed by different people. X apparently had no motive for killing any of the victims, but he/she was connected with all of them.

Hastings is intrigued and suspects all the people staying at Styles in turn. The first mishap occurs when Colonel Luttrell, the owner of Styles, accidently shoots his wife, but she is only wounded and recovers. Then Barbara, Dr Franklin’s wife, who suffers from her nerves and is looked after by Nurse Craven is found dead, poisoned by one of the toxic substances her husband is researching. Finally Stephen Norton, another guest is found dead in his locked bedroom with a bullet hole in the middle of his forehead. It looks like suicide, but there is something about the scene that reminds Hastings of an earlier death.

When Poirot, himself dies, the mystery is unsolved, but there is a twist in the ending, which I didn’t see coming, making this one of my favourite Agatha Christie books. It is also a theatrical and dramatic ending to the book and to Poirot, himself.