Inspired by the traditional ballad, Juniper, Gentian, and Rosemary tells the tale of a mysterious young man who brings magic into the lives of three sisters. The eldest, Juniper, is impressionable and easily swayed. The youngest, Rosemary, is giddy and smitten. And Gentian, the middle sister, is more practical, refusing to be beguiled.

But Dominic begins to fascinate Gentian as well, diverting her from the astronomical pursuits that she loves. Her father begins to fear that the lad may be more than a charmer, perhaps even the Devil himself....