So who did it? The jealous anesthetist (Trevor Howard)? His nurse fiancee (Sally Grey)? The slick, ladies-man surgeon from the big city (Leo Genn)? The hospital matron with the crazy eyes (Judy Campbell)? That's the great, creepy question that drives "Green for Danger" forward. A little-known but extremely watchable black and white mystery from 1946, "Green" just came out on DVD from Criterion -- the Rolls Royce of home video companies -- and while on vacation we all hunkered down to watch it: Lori and I, the girls, and Lori's parents. It's nice to get a cross-generational thing going, and it's rarer than you think.

In this case, the grandparents could talk about the WWII era, which they remembered from when they were our daughters' age. But primarily "Green for Danger" works as a nifty whodunnit -- a bit scary when one of the suspects gets killed off in an operating theater during a dark and stormy night but surprisingly funny when Inspector Cockrill from Scotland Yard turns up to do some snooping. He's played by the British character actor Alistair Sim, the guy who for my money is still the best Scrooge in the best film version of "A Christmas Carol."

Here Sim plays a detective who's smart and who knows it, and whose vanity keeps tripping him up. My girls howled at some of his scenes, both when the Inspector shows he's thinking several steps ahead of the characters and when he turns out not to be as clever as he thought. They came out of the film enjoyably creeped out and hooked on classic British murder mysteries. Some Agatha Christie next, I think.