In a small town near Tampa, a seven-year-old girl named Mary Adler (Mckenna Grace) shows a remarkable talent in mathematics since her first year of school. She already masters advanced mathematical calculations, which impresses her teacher Bonnie Stevenson (Jenny Slate) very much. Mary gets a scholarship to go to a private school for children with special talents. However, her uncle and the girl’s “de facto” tutor, Frank (Chris Evans), refuses this offer. Relying on similar experiences of his family with such schools, he fears that Mary will not have the chance to grow up like a “normal” child. Later, Mary’s mother, Diane, was a very good mathematician and was dedicated to solving the Navier-Stokes problem (one of the seven unresolved issues) before she committed suicide when Mary was only six months old life. From that moment, Mary was raised by Frank. Frank’s estranged mother, and her mother’s grandmother, Evelyn (Lindsay Duncan), seeks to get the girl’s custody and move with her to Massachusetts, because she thinks Mary can be a talent like there’s only one in a million in Mathematics Matter and this talent must be further developed to become a great mathematician. Frank, however, disagrees, and thinks that his sister would have wanted Mary to go to a normal school and have the childhood she did not have.