I enjoyed this Ngaio Marsh (1895-1982) entry a great deal, albeit it's not representative of her very best works such as False Scent (Roderick Alleyn Mysteries), which is yet another theatrical murder mystery, also featuring Scotland Yard's Inspector Roderick Alleyn.
Marsh, a New Zealander, was herself a director of theater so in this instance she naturally established an extensive wallpaper of details before she got around to knocking off her victim. I didn't mind this at all since her background for the mystery was so competently conveyed.
The story is essentially that Theater Director Peregrine Jay is putting on a top-notch production of "Macbeth," a play which reputedly brings bad luck to its principals. An apparent Herculean swing by some unknown cast or crew member's huge sword (a "Claymore" which has a difficult Scottish pronunciation and which is additionally said to have powers of its own!) brings the impending fear of doom to a head. And even though Inspector Alleyn was in the audience watching the play when the murder occurred, he still has a tough time sorting this one out.
I think that it would probably have been nice to have had just a little more of Inspector Alleyn and slightly less of the theater director, but it is what it is. I highly recommend this one for any enthusiast of Ngaio Marsh or, for British cozy murder mystery fans in general.