Do we have this already?
The hero of the story is once again fighting a giant monster, terrorist organization, etc.
The Problem? The hero isn't a monster hunter or an agent in an antiterrorist organization, he/she is just an average person who shouldn't have any reason to be doing these things on a regular basis.
Compare to an unlikely hero, however with multiple movies/a weekly TV show, putting them into that situation more than once.
- Die Hard, the first movie has Bruce Willis, an average albiet badass cop, fighting off terrorists in an office building, which makes him an unlikely hero. but with the sequels he takes down multiple other terrorists, when that is not even slightly his job.
- Buffy the Vampire Slayer is a justification of this trope. All the murder and other violent crime that takes place in Sunnydale on a regular basis could give afghanistan a run for its money, but the hellmouth gives the area a larger paranormal activity than normal. (note: this does not explain Ted the robot in "Ted" nor does it explain the Invisible girl in "Out of Mind, Out of Sight" or the reanimated corpse in "Some Assembly Required" or the Inca Mummy in "Inca Mummy Girl" especially because of all the people she couldve attacked, she attacked Buffy's foreign exchange student.
- Somewhat averted in Firefly. Mal and the Serenity crew dont fall into too mant out of the ordinary scenarios, however they do perform a few history making capers, as well as take in River and Simon Tam who are fugitives from the law, as well as River being the most powerful Psychic in the universe. not only that, but the crew also discover the reasons behind the reavers in The Big Movie, which is kinda a big deal.