When a Christmastime zombie plague strikes a small Scottish town just as the local high school is staging its holiday variety show, Anna (Ella Hunt) and her classmates must sing, dance and slash their way through hordes of the undead. Well, there’s a sentence I’d never thought I’d write. It’s hard to get mad at such an unabashedly absurd genre mashup, and it gets points for trying something new. Though this trifle from director John McPhail (Where Do We Go From Here?) loses steam in the second half, for the most part the young cast’s energy is infectious, the gore is comical and the songs aren’t all that bad. (93 min)