Ugh. I want my three hours back.
This series adapts a lightweight, but perfectly useful, mystery from Agatha Christie and makes it an incoherent mess.
Great production values--as is true of so much TV these days--but indifferent acting (including John Malkovich with an absolutely bizarre accent) and a stinker of a script/story.
No doubt a great deal was spent on period touches, but many of them ring false. Just one example: a framed motto on a bedroom wall that says "God Seest Thou"--which means "you see God." In context, that's not what it's meant to say; it meant to say "God sees you," which would have been "God Seeth Thee"--and anyone producing such mottos in 1930s England would have known it.
Save your time and skip this one.