This story is mostly familiar from Alfred Hitchchock's 1938 movie, starring Michael Redgrave and Margaret Lockwood. Among the things it's best remembered for are the comic double act of Basil Radford and Naunton Wayne, playing the cricket-obsessed Charters and Caldicott trying to get home to England from somewhere in pre-war Europe to watch a Test match, and Dame May Whitty as the titular missing person, Miss Froy.
This new BBC version, dramatised by Fiona Seres, lacked fanatical cricket supporters, though it was more faithful to Ethel Lina White's original novel, The Wheel Spins, which didn't have any either. Also, it restored the young hero Max (Tom Hughes) to his original identity as a British engineer working in the Balkans, rather than the whimsical musicologist played by Redgrave. And the vanishing lady wasn't Dame May Whitty's British spy, merely a governess (Selina Cadell, pictured below) who had stumbled upon a secret potentially harmful to the interests of various politicians and aristocrats.
But you'd have to suspect that Hitchcock made his changes for a reason, adding character and humour and upping the stakes so that there was some discernible point to the abduction of Miss Froy. Here, a very serviceable cast had been assembled to wear attractive period clothes, travel on an antique steam train and strike various attitudes, but there wasn't much drama, nor any particular reason to care whether the lady had vanished or not.
The piece wasn't helped by its brattish and self-centred leading lady, Iris Carr (Tuppence Middleton). We first encountered her as one of a group of over-refreshed toffs who splashed around in the hotel pool, guzzled bubbly, fell down drunk and tried to get off with each other. Elderly sisters Evelyn and Rose (Stephanie Cole and Gemma Jones) looked down their noses with shudders of spinsterish disgust and yearned to get home to their English country garden. The Reverend Barnes (Pip Torrens) and his timid wife (Sandy McDade) adopted a tone of pained forbearance. Mr Todhunter (Julian Rhind-Tutt) was too busy bickering with his mistress Laura (Keeley Hawes, lounging below) to notice.
Long story short, Miss Carr ended up on a trans-Europe express heading for Trieste and ultimately London, surrounded by all the guests from her hotel, mysteriously travelling home simultaneously. Having incurred sunstroke by wandering around the countryside in the middle of the day, she was taken under the wing of the kindly Miss Froy, a governess to a relative of the sinister Baroness. The latter was played by Benedikte Hansen as a pantomimic crone seemingly descended from Young Frankenstein's Frau Blücher, only with a whistling train instead of whinnying horses.
Finding Miss Froy vanished, Miss Carr's panicky attempts to discover her whereabouts were met by a wall of misinformation (she had never existed nor had tea with Miss Carr, or if she had she was somebody else with a German name, and obviously sunstroke had addled Iris's brains). Happily, young Max took pity on her, despite the misgivings of his travelling companion (Alex Jennings). Inevitably, the Baroness's evil cronies were found out, Miss Froy was rescued from the luggage van, and Max and Iris skirmished flirtatiously. It felt altogether vague and inconsequential. A decent Marple or Poirot would knock spots off it.