Writer-sleuth Mallory (Kill Your Darlings, etc.) now comes from Iowa to N.Y.--to see his agent and then to join the festivities at the Mohonk Mountain House resort, site of those well-known ""mystery weekends."" Mallory, along with other mystery writers, is scheduled to play the role of a suspect in this weekend's murder game. The victim is to be played by none other than ""articulate but mean-spirited"" Kirk S. Rath, ""the most famous and controversial critic in mystery circles."" (Kirk S.? Yes, indeed: when Mallory quotes one of Rath's put-downs, it's verbatim from a Kirkus pan of a recent Collins effort.) What soon happens, of course, is that nasty Kirk is really murdered: Mallory witnesses the killing from afar (or thinks he does), later finding the snowchilled body while hiking with girlfriend Jill. The suspects include all the writers present, most of whom ""have suffered career setbacks because of Rath."" But the actual murder motive--unpleasant as well as implausible--comes from out of left field as Mallory wraps things up in a style more in tune with old Charlie Chan movies than contemporary detective fiction. Some in-joke amusement for Collins' writer-friends, perhaps, and Mallory's narration is often crisply engaging--but this is flimsy doodling overall: a sad comedown from the real distinction of Mallory's last outing, A Shroud for Aquarius.