Saving Santa (2013)
More on that in a moment. First, the plot.
Bernard D. Elf, astonishingly only the second-worst-named character in this movie, wakes up late for an appointment showing off his new invention to the North Pole's tech company. He races across town and gets them to watch, but in the process momentarily blacks out the elf city's power.
The time the grid's down is just enough for Neville Baddington (and that'd be #1) and his evil package delivery company to determine the cloaked location of Santa's operation. Unaware they're on their way, Bernard heads to his day job, shoveling reindeer dung out of Santa's stables.
While there, he runs into the big man, who lets him in on a secret. He shows Bernard a time travel device built into his sleigh that allows him to make it to every house on Earth. Only there's a catch - you can't actually change the past. Going back in time creates a second version of yourself, but your original is still destined to go back, etc., etc.
When Baddington's goons invade and capture Claus, Bernard ignores this limitation and starts circling back to relive the day. When he realizes he caused the blackout and subsequent invasion, he tries to sabotage his prior self to keep him from making it to the meeting (he's the reason his alarm clock didn't go off, and so forth).
Here's the impressive part - they were pretty consistent about playing by these rules. Go back and re-watch the first few minutes, and you'll be able to pick out other iterations of Bernard ducking out of sight and so on. I can't say they were perfect: there's a recurring gag about him and some secret agent elves hiding against murals, and the movie gets a touch sloppy with that continuity. There's also at least one point where the timelines don't quite logically line up, thanks to a musical number.
But overall, it handles time travel surprisingly well. As for every other element of the movie... not so much.
The jokes just aren't funny, the dialogue is awful, the character designs are simplistic and uninspired, the animation is cheap, the songs (did I mention this was a musical?) are tedious, the voice acting...
Actually, the voice acting is fine. Bernard is played by Martin Freeman, and Baddington is played by Tim Curry. They don't save the movie, but they try their best.
The movie wedges in a love interest in the form of a special agent elf who believes in, assists, and eventually falls for Bernard, because... I guess because white male movie heroes always get a love interest as added proof that they're special.
The resolution is a little better. Bernard learns enough to be able to set things right. He can't change the past, but he can alter the future using what he's discovered.
I also appreciate that the movie goes in an interesting direction around it being dark at the North Pole during Christmas. Visually, the city appears to be in daylight, but this is revealed to be a hologram connected to the cloaking device hiding them from the world. They don't dwell on this or explain it in depth, but if you know to look for it, it shows they actually gave the matter some thought.
Likewise, there's an insinuation Bernard will eventually go back in time and invent the time travel device - pretty clever for a movie that devotes a great deal of time to reindeer fecal jokes.
Ultimately, this is a bad movie that uses its central element unusually well. For those of us obsessed with unusual holiday films, it's a fascinating inclusion. But the rest of you would probably be better served skipping this.