A Fierce and Subtle Poison is based on, or at least owes some inspiration to, “Rappaccini’s Daughter”, a work of science fiction by Nathaniel Hawthorne about a scientist’s daughter who becomes immune to poisonous plants but poisonous herself to others. Samantha Mabry transposes the setting to present-day Puerto Rico and ages down the cast a little; Lucas becomes a high school senior on the verge of college studies, spending one more summer in Puerto…