A serial killer is murdering apparently random people in order of their names: first Alice Ascher of Andover, second Betty Barnard of Bexhill-on-Sea, third Sir Carmichael Clarke of Churston (a small village). The killer sends a letter to Hercule Poirot before each murder, telling him where and when each murder will take place, but Poirot and the police always arrive too late. The killer signs himself 'ABC' and at the place of each murder, leaves an ABC Railway Guide next to the body.
Poirot and the police are baffled until a series of clues lead them to suspect the murderer is traveling as a stocking salesman. Then the 'D' murder in Doncaster goes awry - the wrong person is killed. Then, a stocking salesman called Alexander Bonaparte Cust walks into a police station and surrenders.
The case seems closed, but although Cust has confessed to the crimes, he claims not to have heard of Hercule Poirot and cannot explain the letters, although they were written on his typewriter. Cust suffers from epilepsy and is subject to blackouts. He claims he can not recall committing the murders, but he believes he committed them because he was in the vicinity of each crime scene. He also sees other clues, such as blood on his cuff and believes himself the culprit. Poirot is suspicious and is later able to prove that Cust is innocent of the crimes, particularly when a man is able to provide an alibi for Cust when he was meant to be murdering Betty.
In a twist ending Poirot reveals that the brother of Sir Carmichael Clarke, Franklin Clarke, who wanted Sir Carmichael's property and money, committed the crimes in order to draw attention away from the murder of his brother; simply killing his brother would have automatically drawn attention to himself, whereas creating the illusion that his brother was the victim of a serial killer would draw attention away from looking for an individual motive for the crime. Franklin had met Cust by chance and decided to use him as part of his plan. He arranged for Cust to be hired as a stocking salesman and gave him a travel itinerary that ensured he was at the scene of each murder. It is also revealed that Clarke had put the blood on Cust's cuff. He also sent Cust a box of ABC Railway Guides and a typewriter, on which he had already typed the 'ABC' letters.
The thing i love the most about the Poirot books is that i always either think im sure about who and how things happen, or i have absolutly no idea of how the murder could have been pulled off. On every occasion i get a surprise at the end, because it is never who or how i thought.
The a.b.c murders is no exception to that rule. The swaping narrative makes you think you know the whole story. But at the end, nothing turns out how you thought it was.
