From IMDB:

Is a trio of witches responsible for a series of sudden deaths or is there a rational explanation?

From Amazon Prime you can stream both hour-long episodes of this mystery story supposedly based on a story by Agatha Christie.

But don’t bother with this adaptation. Thank to a warning found in IMDB:

Sarah Phelps “version” is a complete mess. The production has an excellent cast including Rufus Sewell, who is magnificent as usual. The set design and costumes are top notch and even the cinematography and music are good, but…

Sarah Phelp’s story, script and directing are terrible. She makes an utter train wreck out of the original story and what’s left makes no sense at all. I can only hope that Sarah Phelps writes and creates her own scripts for future projects as she has no talent adapting existing stories.

Much of what the reviewer says rings true. Oddly enough I enjoyed watching what is essentially a good production. Indeed Rufus Sewell is very good.  But the ending left me confused.

If you are interested, read the Wikipedia account of the novel where you will see that there is very little in common with the two versions.

Skip this unfortunately watchable mess.