Chris Evans stars in this heart-warming drama about an uncle who becomes a father to his young niece. Frank Adler (Evans)'s world changes when he takes in his niece Mary (Mckenna Grace) and his paternal instincts kick in when he realises that he has to protect her from the world. Mary is not an ordinary child; she is a mathematical genius capable of calculating large sums in her head. As per his late sister's wishes, Frank intends to give Mary as normal a life as possible, enrolling her in a mainstream school to attend regular classes with children her age. When Frank's mother Evelyn (Lindsay Duncan) finds out just what her granddaughter can do however, she forms her own plan for Mary's future and sets about obtaining full custody so that she can control Mary's education. As he faces losing Mary to his formidable mother, Frank must fight with all his might to keep Mary in the life that she deserves. The cast also includes Octavia Spencer, Jenny Slate and Julie Ann Emery.