Mattie Cook, her grandfather, and her widowed mother reside above the family coffee shop in the summer of 1793. Mattie spends her time planning how to make the family business the best Philadelphia has ever seen while avoiding duties. But soon a fever starts to spread. Disease spreads over the city, obliterating everything in its path and upending Mattie's entire life. Mattie and her grandfather leave the city at her feverish mother's urging.