“Evil Under the Sun” is a classic Agatha Christie whodunit featuring the mustached sleuth, Hercule Poirot. Peter Ustinov plays the famous Poirot for the second time, following “Death on the Nile (1978)”, and just as in the previous movie, he is supported by a stellar ensemble cast.

As with most whodunits, the plot involves the solving of a murder in a locale with quite a few possible suspects, but only a finite number. In this case, the victim is an actress, and each suspect has an axe to grind. So, any one of them could have done it, right? Wrong! It turns out that in this case, each and every one of them has an alibi. So, how was she murdered then? That’s where the genius of Agatha Christie and her sleuth come in.

The movie begins with the police investigating the murder of a woman in North Moors, England. The relevance of this investigation will not be revealed in the plot until the very end.

The plot now shifts to Hercule Poirot being employed by an insurance company to investigate the case of a mysterious fake diamond allegedly gifted by millionaire Sir Horace Blatt (Colin Blakely) to his lover, Arlena Stuart Marshall (Diana Rigg).

Poirot meets Blatt and learns that Arlena dumped him shortly after he gave her the jewel and then married someone else. Blatt alleges that Arlena could have switched the real diamond with a fake to con both himself and the insurance company.

Blatt informs Poirot that Arlena is now vacationing in an exclusive hotel on an island that caters solely to a wealthy clientele. In the novel, it is Burgh Island in England. In the movie, it is an island in the Adriatic Sea. Filming, however, was done at several scenic locales, including Majorca and Sa Dragonera.

Further, Blatt tells Poirot that the hotel is now owned by Daphne Castle (Maggie Smith), which used to be the summer palace of the King of Tyrania. The king gifted her this palace for unknown reasons, and Daphne enterprisingly transformed it into a hotel.

Needless to say, Poirot takes on the challenge and goes to this intriguing venue. Sure enough, Arlena is there too, with her new husband Kenneth (Denis Quilley) and his daughter, Linda (Emily Hone), whom she mistreats.

Accompanying them are Patrick (Nicholas Clay) and Christine Redfern (Jane Birkin), a young couple. It is revealed that Patrick is Arlena’s secret lover and Christine is not happy about that.

Also with them is the writer Rex (Roddy McDowall), who stands to make a sizable income by writing Arlena’s biography, but Arlena would not authorize it. There are also the Gardners (Sylvia Miles and James Mason), movie producers who hate Arlena as she has caused them a major financial loss.

Daphne also dislikes Arlena. Sure enough, Arlena is found murdered on the beach of the island, and everyone on the island is a potential suspect. Around this time, Blatt too comes to the island.

Now, while it is true that everyone has a motive to commit the crime, Poirot’s interrogation of the suspects would reveal that each of them has a seemingly credible alibi.

With such a predicament, who or what could have committed the implausible murder? It would be up to Poirot and his gray cells to unlock this puzzle.

The plot has a strong similarity to Agatha Christie’s “Death on the Nile”, which also features the murder of a rich woman and a number of suspects, each having a motive to kill her. The key difference is that while most of the suspects had an opportunity to commit the crime in “Death on the Nile”, in this case, none of the suspects could have possibly been able to murder the victim.

Ustinov impresses as Poirot, and the ensemble cast, studded with veteran Thespians, also delivers. The venue for the plot that I alluded to earlier is breathtaking and adds to the allure of the film. All in all, “Evil Under the Sun” is a great watch.