I've just finished watching
The ABC Murders, a 3 part mini series from 2018.
It starred John Malkovich as Poirot and Rupert Grint (yes! Ron Weasley!) as Inspector Crome. It was interesting but really didn't feel like an Agatha Christie. It was adapted by Sarah Phelps (who also adapted And Then There Were None in 2015) and it was much darker and grittier than the book.
It's 1933 and Poirot is no longer a celebrated detective. He is alone and lives a solitary life. He receives letters from "ABC". Strange and taunting letters. When he takes them to the police, he discovers that Japp has retired and Inspector Crome is not interested in listening to him. And then the murders begin.
The book and mini series stick to the same basic plot:, a series of murders are committed by "ABC", who sends letters to Poirot about the murders he will commit. The first victim is Alice Ascher (Asher in the mini series) in Andover, the second is Betty Barnard in Bexhill, and the third is Sir Carmichael Clarke in Churston. The fourth murder takes place in Doncaster. An ABC Rail Guide is left beside each of the victims.
Spoilers under the cut.
The main suspect is a travelling salesman called Alexander Bonaparte Cust. In the book he has epilepsy but, in the mini series, he also has something (I missed what) that causes terrible pain, so he hires his landlady's daughter to walk on his back and dig the sharp heels of her shoes in to blot out the pain. After he's cleared of being a killer, he has an operation on his brain and it's left unresolved as to whether he ever wakes up.
The real killer (book and mini series) is revealed as Franklin, Sir Carmichael Clarke's charming but ruthless brother, who was determined to inherit Sir Carmichael's wealth and title. In the book, Sir Carmichael's in love with his secretary, Thora Grey, and plans to marry her after his gravely ill wife passes. In the mini series, Frankln and Thora are having an affair and she's left destitute and disgraced after his arrest. It's strongly implied she becomes a prostitute.
John Malkovich's version of Poirot was a sad and lonely figure. There was no fun or humour to him at all. He had frequent flashbacks to a field in Belgium, though you didn't find out the significance until the end. It was revealed then that he had never been a policeman but had been a priest. In 1914, his church was burned down and his congregation murdered by invading German soldiers. Poirot had been struck down beforehand by an officer and was the only survivor.
I was really impressed by Rupert Grint in this though. He was completely convincing as Inspector Crome, who starts by loathing Poirot and ends up admiring him.
In the end, this was interesting but there was no warmth to it at all. It was nowhere near as rivetting as And Then There Was None and had a very stark "kitchen sink drama" feel to it. Everyone had awful lives. I ended up mainly watching for Rupert Grint as he was the best part of it all.