I did not realise that this was the opening episode. It is, however, typical Christie. A seemingly minor problem - the missing cook - becomes something much bigger once Poirot gets his little grey cells involved.
The way the story develops is perhaps a little obvious and we are in the world of disguises again, but it is not quite too obvious and is very watchable.
I particularly like Bridget Forsyth as the cook's employer. I still remember her from The Likely Lads and she still does righteous indignance very well, being more than a match for Poirot.
All in all, a little convoluted, but definitely worth watching.