Polly Longden's china-doll looks belie a strong and fiery personality. When typhoid strikes her home city of Lincoln, she needs every ounce of that strength in order to cope. With the death of her mother, thirteen-year-old Polly has to give up her ambition of becoming a teacher to care for her family. When their father, too, falls victim to the typhoid, his only hope is to go to hospital, leaving Polly to cope alone. Thankfully she has the support of her neighbours: Bertha Halliday and her son, Leo, a young policeman.