What does it mean to be “gifted?” Movies and television don’t do a very good job of portraying what it means to be cognitively advanced, and this one is not close to being realistic, with a first grader who reads up on the problems of the EU and can identify a missing minus sign in an equation several lines long. And she is adorably missing those top front teeth for a really long time when anyone who has ever been the family tooth fairy knows that the new ones come in pretty fast. What we learn from this is that the movie does not want to take any chance that you might need a reminder of how endearing it all is. Everything looks dipped in honey and the script is gooey, too, like a lesser Hallmark movie. But Chris Evans’ sensitive, deeply affecting performance and genuine chemistry with McKenna Grace as his brilliant niece are so honest that it captivates us anyway.

Evans is Frank, who repairs boats and lives with Mary (McKenna Grace) in a tiny apartment in Florida. They have an easy rapport and are completely at home with each other. Mary is also close to their neighbor Roberta (Octavia Spencer). Mary is cognitively advanced, very curious, sometimes impatient, and sometimes anxious due to her reading about the world economy. Frank has been teaching her at home, but she is about to start first grade at a public school because he wants her to be with other children and to be more of a child herself. “Try being a kid,” Frank tells her as she gets on the bus. He does not really think it is possible to “dumb her down into being a normal kid,” or that it would be the right thing to do if it was, but he would like her to have the chance to make friends with children her own age and learn how to play.

It does not take long for Mary’s new teacher, Bonnie (Jenny Slate) to figure out that Mary is truly gifted, after she has to take out her calculator to check Mary’s computations. Frank’s attempts to deflect her attention are unsuccessful, but Bonnie appreciates his commitment to trying to create some kind of normalcy around Mary. She also appreciates Frank. Though they both know it is not a good idea for Mary or for Bonnie’s job, they begin a relationship.

And then Evelyn (a nicely frosty Lindsay Duncan) shows up. She is Frank’s mother and Mary’s grandmother. She brings a laptop for Mary and a message for Frank: she wants Mary to get an education commensurate with her ability. “She’s not normal and treating her as such is negligence on a grand scale,” she says. We will learn more about why that matters so much to Evelyn and why Frank refuses when they take the custody fight to court.

Of course we know whose side we should root for and where it is all going. This movie has a lovable one-eyed cat, for goodness sake. But Evans and Grace have a little bit of magic that shines through.

Parents should know that there are some mature themes in this film including a custody battle, a sad parental death by suicide (off-screen) with some strong language, sexual references and a non-explicit situation, alcohol and cigarettes.

Family discussion: Would you like to be as smart as Mary? Why didn’t Mary’s mother want Evelyn to know what she had done?

If you like this, try: “Searching for Bobby Fischer” and “Little Man Tate” — and “Captain January” with Shirley Temple