It wasnt' blackmail -- at least not the ordinary kind. Donald Lam had come to San Francisco to see what he could do for a client who had, it seemed, been indiscreet and had received a letter threatening to tell his wife all. But when Lam met Lois Marlow, she denied a blackmail attempt and was very friendly. She even asked him to mke coffee while she dressed. "You watching that coffee, Donald?" she called through a crack in the bedroom door. "Not yet. A watched pot never boils." She opened the door. The light streaming through the bedroom window made an intriguing silhouette. "Your slip's showing." Lois looked down at the silhouette and laughed. "Some slips don't show, Donald." (Erle Stanley Gardner writing as A. A. Fair)