Jessamine Luxton has lived all her sixteen years in an isolated cottage near Alnwick Castle with her father, Thomas, a feared and respected apothecary. His pride and obsession, a poison garden, contains exotic and local specimens of the most dangerous plants in the world. But Jessamine is absolutely forbidden to enter. Her life changes forever the day a traveler brings a stranger to their cottage, claiming that the young man has special gifts that Thomas might value. Jessamine is intrigued by the young man, who goes by the name of Weed. He has an intense sensitivity to growing things, and an even rarer and more specialized knowledge about plants than Thomas does. As Jessamine falls in love with Weed, she learns his extraordinary secret—and is drawn into the dangerous world of the poison garden in a way she never could have imagined.