Though her short life was vividly presented in Mister God, This is Anna, its huge success led to Fynn being inundated to write more about his experiences with her. Anna and the Black Knight introduces us to Mister John, a veteran of World War I and local schoolmaster, who was to have a profound effect on Anna. Anna's astonishing capacity for looking at things from fresh perspectives, and her fascination with mathematics and Mister God, stands her in good stead as her life is opened up to new things, such as school, priests and motor cars.