J.K. Rowling, embarking on her new, post-Potter blockbuster franchise with "Fantastic Beasts and Where to Find Them," has said herself that her screenplay, which she began several years ago, was informed by world events - particularly, she noted, a rise in populism around the globe. And so there's definitely some darkness in "Fantastic Beasts," despite its being a family film, complete with the sweetest little beasts imaginable - expect to see your kid melt forthwith over the lovable jewelry-imbibing Niffler But there's also a refreshingly light tone competing with the sinister themes, thanks especially to two exceedingly appealing supporting characters headed for a sweet confection of a romance.