SINISTER HOUSE Gail Hollister has been sent to Casa de Ayer to organize Colonel Conniston's antique collection. Her first surprise occurs when she is stopped along the way by an unsuccessful highway robbery, particularly since she recognizes the would-be thief-Kerry O'Neil. Later that evening, having finally arrived at the Colonel's old California estate, she is shown the intaglio gems that Kerry had been trying to steal. And still later, she is shocked to discover Conniston's dead body on the library floor! Police detective Bartlett is convinced that Gail had something to do with the death, that she helped her friend Kerry break into the tightly-locked house. Bartlett knows about the failed robbery, but Gail knows that Kerry couldn't have committed murder. And now it's up to Gail to figure out who did kill Conniston. Could it have been his trusted aide, Dimity, who always seems to be lurking behind doorways? Or Norman Stark, the Colonel's son, whom she has a really bad feeling about? All she knows is that she had better move fast, or both she and Kerry are likely to end up in prison.