Typical Christie. This was her 1941 book.

A group of people ALL could have been the killer.

The surprise ending seemed to cute and complex (to me) to be believable.

Hercule Poirot takes a holiday in Devon.

During his stay, he notices a young woman who is flirtatious and attractive, but not well liked by a number of guests.

When she is murdered during his stay, he finds himself drawn into investigating the circumstances surrounding the murder.

wikipedia