China Bayles and Ruby Wilcox are offering their popular “Not Just Plain Vanilla” workshop when, across town on the campus of Central Texas State University, a botany professor (an expert on the vanilla orchid) is found dead in his greenhouse. Does this story begin with a passionate desire for an exotic flower and its costly, delectable fruit? Does it start in a corrosive desire for revenge? Or is the professor’s death the result of a bizarre black-market orchid-smuggling scheme gone awry?