Murder on the Orient Express
After much investigating, intrigue and mystery Poirot (Kenneth Branagh) comes to the conclusion that all twelve of his suspects participated in the murder of Ratchett/Cassetti since they'd all suffered greatly when he murdered Daisy Armstrong years earlier.
Deciding they've all suffered enough, he decides not to reveal this to the police and instead claims Ratchett was killed by someone who fled the train.
Poirot's plans for a holiday are curtailed again as he is called to Egypt to investigate a Death on the Nile (get it?).