I began watching this and had the feeling I'd seen the story before or read it years ago. Then I realized I had seen another version made in 1986 with Tony Curtis and Peter Ustinov essaying the principal roles.
In this version, MARTIN SHAW (an actor who strongly resembles Claude Rains both physically and in manner), does a standout job as Sir Charles, an actor who is famous for his dinner parties for his wealthy friends and theater associates. David SUCHET is Hercule Poirot, who suspects that a second death among Sir Charles' associates is tied somehow to the first one which was judged to be death from natural causes.
Plot development is typical of any tale by Agatha Christie--with lots of clues along with the usual red herrings. And it's given more serious treatment than the former version with Tony Curtis as the wealthy party giver.
The production gets meticulous production design, gorgeous outdoor settings, all photographed in vivid color so that it has all the trappings of a Grade A movie suitable for the big screen.
Although I guessed "who dun it" long before the tale was over, I admired the way Christie dropped her clues and set the stage for one of her more intricate stories of deception and murder among the jet set. And MARTIN SHAW does a standout job in an excellent cast of British actors.
It ends on a rather tragic note, with Poirot realizing how close he came to death himself.