With the Hallmark Channel airing sappy Christmas movies around the clock and the timeless classic “A Christmas Story” on tap to do its own annual 24-hour marathon on the TBS network Christmas Day, it might be hard to think of how any movie could provide a freshly entertaining take on the ultimate holiday. If you’re willing to see something stunningly inventive, however, the new British import “Anna and the Apocalypse” is the movie of your dreams.

Starring a cast of complete unknowns, “Anna” is the story of a Scottish teenage girl named Anna (Ella Hunt) who has to navigate the usual teenage travails of boys, high school and how to establish her independence from her overly concerned widowed father. That might seem to be plenty to deal with for any girl, but one morning she wakes up, pops in her earbuds and sings and dances her way to school while being completely oblivious to a hilarious array of zombie anarchy occurring throughout her town.

Anna dreams of leaving her small-town, working-class Scottish existence completely behind at graduation, although she feels a bit guilty over the prospect of leaving her school-janitor father alone. She’s also caught in between her longtime best friend John (Malcolm Cumming), who pines for her with a naive purity of heart, and the bad-boy jock Nick (Ben Higgins), who’s constantly hitting on her.

At first, these teens’ songs (by Roddy Hart and Tommy Reilly, and available for free streaming at Amazon Prime) focus on the daily angst of living, boosted by hilarious lyrics and a propulsive power-pop score that backs up amusing choreography. But as the zombies take over the town and utterly destroy the school’s Christmas musical, both Anna and the movie overall shift into an ever-unpredictable series of battle royales that involve an incredible array of makeshift weapons to kill off the undead.

Make no mistake, there are lots of gross-out moments along the way, with plenty of chopping, stabbing, gouging, and decapitations meted out by the teen heroes against their monstrous oppressors. But writers Alan McDonald and Ryan McHenry serve up plenty of wicked laughs as well, which keeps the film from crossing the line into gruesome unpleasantness. And there are some great satirical elements, with many of the town’s teens cluelessly posing for selfies next to zombies as they evacuate, only to find that the zombies chomp them while they’re lining up the perfect shot.

All the fun was pulled off on an extremely tight budget that required some dance numbers to be improvised just before the cameras rolled. “Anna” had its roots in a short film called “Zombie Musical” by McHenry, and perhaps the saddest thing about it is the fact that McHenry died of cancer at age 27 in 2015 and never got to live to see his dream project hit screens worldwide.

The proceedings do get a bit repetitive as the movie goes on, but “Anna” also manages to have some affecting moments of loss and contemplation en route to its finale. Overall, director John McPhail ensures that an anything-goes sense of fun saves the day, even if these plucky kids can’t always save their town and their loved ones.

“Anna and the Apocalypse” Grade: B