Murder at Mallowan Hall
By Colleen Cambridge. (Kensington, 272 pages, $26.)

The real mystery of "Mallowan" is: Why would you write a crime novel that is set in the late Agatha Christie's house but have her play only a walk-on role? Christie, whose married named was Mrs. Max Mallowan (although the real home she shared with her second husband is called Greenway House) is hosting the kind of homicide-prone weekend party that was popular in her books. She's too busy making sure everyone has crumpets to solve the murder of a young man who turns up, uninvited, at the party, so her brisk assistant, Phyllida Bright, does the detecting (the book's cover optimistically bills it as "A Phyllida Bright Mystery" although it's the first in a proposed series so "The Phyllida Bright Mystery" is closer to the mark).

Bright shows promise as a sleuth but Cambridge buries key information very late in the book and her suspects are too indistinct for us to fasten on any of them as possible killers. So we spend much of the book wishing the real Christie would pop in and make everything better.