Evil Under the Sun
From a story by Agatha Christie
If you like your mystery cinema on a grand scale then you won't want to miss Evil Under the Sun. It starred Peter Ustinov as Agatha Christie's famed detective Hercule Poirot, as did Death on the Nile (1978), which I reviewed here, and Appointment With Death (1988). Ustinov also played the same role in a trio of TV movies which were made in the Eighties.
I've never heard anyone use the term "epic mystery," but it wouldn't be out of line to use it to describe this movie and Death on the Nile, in which it seems that nearly every component, from performances to setting to cinematography to score, is somehow larger than life. Plus there's the usual cast of notable actors on hand to fill the other roles, including Maggie Smith, Roddy McDowall, James Mason, and Diana Rigg.
As for the plot, about all I'll really say it is that it worked for me. I haven't read the book yet so I can't make any comparisons, but at the core of things are a few murders and a missing gemstone, which M. Poirot is working to locate. Which task takes him to a (presumably) Mediterranean island resort where most of the action plays out.
Perhaps a more persnickety reviewer than I could have found something not to like about this one, but aside from the fact that many of the performances bordered on being downright over the top, I couldn't find much to quibble about.