There's a new song. If you have children under 12, soon you're going to know it like you know your own name.

Soon, your daughter will be belting it out at full volume when you're trying to get her to brush her teeth.

Soon, YouTube will be crammed with videos of toddlers, lip-syncing teens and men in dresses singing it.

Soon, contestants on the X Factor will be testing their Mariah-inspired vocal gymnastics against it in an attempt to make Iggy Azalea smile. She won't.

It's called 'How Far I'll Go' and it's from the Disney movie, Moana. It's written by Lin-Manuel Miranda. You might have heard of this other thing he wrote—a musical called Hamilton.

And with that chorus earworming its way into the brains of little people everywhere, it's official. The three-year-long Frozen era is finally over. There's a new heroine in town.

Thank God.

Not that we didn't love Frozen. Those of us whose children passed through the preschool years during Elsa's reign will always carry the bittersweet scars. Our daughter's photos in that ubiquitous blue, polyester dress. The parties featuring a drama student in a blonde wig handing out Olaf-pops. The frustration of trying to perfect snowflake icing.

We've paid our dues. We've earned Moana.

If you've looked at the posters and thought the star of this animated movie is the fearsome-looking demigod, Maui (played by The Rock, a.k.a Dwayne Johnson), you're wrong. It's all about the girl.

Moana (played by Hawaiian teenager Auli'i Cravalho) is not a princess. She's not a queen. She's the daughter of a Polynesian island chief, and she is learning how to run stuff.

Moana is brave and smart and curious and strong. For once, Disney hasn't drawn her so thin that she might blow over in a stiff breeze. She has feet solidly grounded, legs that can weather a storm and she never even mentions romance, or husbands, or Prince Charmings. Not even once.

Yes, people, Moana is a kids' movie that passes the Bechdel test. When the teenager confides in her wise grandmother, it's not about boys. It's about destiny. And power.

Moana doesn't need saving, not even by Maui. In fact, her smarts save him, again and again.

The plot also has Moana saving her home island, the fictional Motunui, from the fury of a lava demon that is turning lush vegetation to ash and soot across the oceans. The island she is destined to govern was, like all the other islands, pulled from the turquoise sea by Maui, who dominates creation legend from Samoa to Tahiti to New Zealand to Hawaii.

She has to find him and rescue him from exile to help her cause. So she disobeys her family and takes to the high seas.

Alongside Cravalho and Johnson, the cast includes Maori actors Temuera Morrison and Rachel House. The plot and its depictions of legends were run closely past a group formed with the animators over the course of years—the Oceanic Story Trust—to make sure it wasn't stomping all over culture. The result is a diverse, celebratory, respectful, joyous jewel of a family movie. 

But back to our girl. And that song.

Just listen. You'll get it.

But why all the fuss? Why do mothers of daughters cling on to positive role models tighter than an affordable childcare place? Because we all know how much they matter. We see it every day. When a TV show or a movie slides into view, our children don't choose who they "like", they choose who they'll "be". And, as we all know by now, you can't be what you can't see.

What little girls see when they look at Moana is a heroine for a Trump era. She's not white. She's not frail. She's not in need of a knight in shining armor.

She knows her mind. She knows her strength. She knows the power of a big, schlocky ballad.

Move over Elsa, with your heels and your angst and your endless braid. Here comes a heroine who's not afraid to get her hair wet.

So, please, take all the small people in your life to see Moana. Just don't whine to me when they won't stop singing that song.