All six RKO whodunits based on Stuart Palmer's canny schoolteacher/amateur sleuth and her flinty foil, Inspector Oscar Piper, are collected in a three-disc set. The surfacing of a stockbroker's corpse at an aquarium sets Withers (Edna May Oliver) and Piper (James Gleason) out to crack the "Penguin Pool Murder" (1932). Robert Armstrong, Mae Clarke co-star. The duo has to determine who erased Withers' music teacher colleague in "Murder on the Blackboard" (1934). Oliver, Gleason, Bruce Cabot, Regis Toomey star. Hildegarde's Catalina vacation gets sidetracked when a fellow plane passenger doesn't survive the trip in "Murder on a Honeymoon" (1935). Oliver, Gleason, Lola Lane star. Withers (Helen Broderick) concludes that a thrown rider's death was no accident in "Murder on a Bridle Path" (1936); with Gleason, Louise Latimer. "The Plot Thickens" (1936) as Withers (ZaSu Pitts) looks for a link between separate slayings. Gleason, Paul Fix co-star. And Withers and Piper encounter backstage murder at a Broadway opening night in "Forty Naughty Girls" (1937); with Pitts, Gleason. 7 hrs. total on three discs. Standard; Soundtrack: English Dolby Digital mono.