Leeloo Brantley never dreamed she'd run into Nate Marshall, her long-time secret crush, after he graduated high school the year before. Yet there he is, standing in Festivities, her mom's party shop, a few days before Christmas with his brand new stepsister, four-year-old Anna. Nate tells Leeloo he's babysitting Anna while their parents honeymoon. Leeloo tells Nate he's not up for it, a fact proved when he calls her in desperation later that night begging for help.
Certain this is an early Christmas present straight from the elves, Leeloo eagerly agrees. And as the three of them begin to hang out under the decorated tree, Nate actually seems to see her with new eyes. Then a weather front brings scary thunderstorms no four-year-old can love. Though Nate assures Anna he'll keep her and Leeloo safe forever, Leeloo has to wonder if he really means it or is simply trying to soothe a beloved little sister who's afraid of thunder.