"Mystery In White" is a 1930's version of a Christmas Special drama,
It's set on Christmas Eve, a fierce snowstorm, strangers on a stranded train grouping together to look for a way out of moving on with the plans for Christmas, an empty but unlocked Country House in the depths of the English Countryside, with fires lit and food laid but with no one inside.
What follows is a series of "TA DAH!" moments as murders and mysteries are uncovered and we learn more about the group of strangers and, eventually, the occupants of the house.
The strangers are all from central casting: the bright, young charismatic upper-class but friendly brother and sister, the heart-of-gold showgirl, the blustering old bore, the tongue-tied socially awkward clerk, the East End ruffian and the de facto leader of the expedition, a fierce, unconventional old man who claims the ability to see the dead and who assumes the role of detective, magistrate and ghost hunter.
This is a book that is bursting at the seams with ideas and people but often doesn't seem to be sure what to do with them. This was a time when genre boundaries had not yet been set and this perhaps explains why sometimes this reads as a Christmas Ghost Story and sometimes as a "The Rivals Of Poirot Christmas Special".
What the book lacks in discipline and character development it makes up for in sheer brio and a Saturday Matinee fascination with adding yet another plot twist.