When a reserved college professor has her work stolen by an egotistical co-worker, she teams up with her assistant, a repo agent and a local tour guide to prevent him from unleashing an ancient demon on the world.
You’ve buried the story.
Try a rewrite like this:
To stop the realise of ancient demon a reserved college professor, his assistant, repo agent and a local tour guide team up to get back the professors work that would make the demons release happen.
Way too long. Now try and focus on emotion and needs not plot.
Do a rewrite and unbury the story.
Agree with CraigDGriffiths.
And in the original version it’s not clear what the cause-and-effect relationship between the stolen academic work and the unleashing of the demon. What is there about the academic work that can enable someone to unleash a demon?
Yep, the Demon thing seems out of place unless you mention this professor is an expert in demonic practices so we have the setup.
I would cut who they team up with for simplicity and just focus that their works have been stolen and about to be used to end the planet as we know it.