You've likely heard of the historic Apollo 13 [mission]. But do you know about the mathematical genius who made sure that Apollo 13 returned safely home? As a child, Katherine Johnson loved to count. She counted the steps on the road, the number of dishes and spoons she washed in the kitchen sink, everything! Boundless, curious, and excited by calculations, young Katherine longed to know as much as she could about math, about the universe. From Katherine's early beginnings as a gifted student to her heroic accomplishments as a prominent mathematician at NASA, this is the story of a groundbreaking American woman who not only calculated the course of moon landings but, in turn, saved lives and made enormous contributions to history.