In 1889, the fledgling town of Rejection, Nevada is populated by the ancestors of the characters who are clearly established as having recently arrived there in the first Tremors movie, because this is, after all, Tremors 4 and anyone who might by bothered by that sort of thing stopped watching at least three movies ago. Rejection's reason for existing is the nearby silver mine which has, unfortunately, elected to resolve its flooding problem by diverting the local stream into a nest of monster eggs. This goes poorly for the miners other than Juan, a miner of decidedly middling ability who was just working there to earn money to pay off his family's ranch.

Fast forward six months, the mine has closed, and Rejection has been abandoned except for Juan, the Chinese General Store Owner and his Wife, the obligatory Cute Kid, the Innkeeper with a Heart of Gold (no that's not a euphemism; she's the Hooker-with-a-Heart-of-Gold trope, but she's really just an innkeeper -- this movie is as resolutely prostitution-free as the Southern Baptist Convention imagines itself to be), the Crotchety Old Guy, and the Native American. Other than the inn and the general store, everything is closed and blown away, and even those two businesses are false fronts with tents behind because the filmmakers town is so poor it can't afford walls.

Into this desolate scene arrives the Mine Owner from Out East (Michael Gross, of course), come to see why his mine has shut down. He hires some random cowboys to investigate the mine for double pay, and they save him a bunch of money by getting eaten in front of him and Juan. Realizing that this is out of his league, Michael uses his last gold coin to hire renowned gunfighter Black Hand Kelly to take on the monsters. There follows an extended set piece of Michael, Juan, and Black Hand wandering around in the desert, with Michael bumbling ineffectually like a rich, pompous Easterner. If any of it was actually funny, one might worry that this movie was actually sort of a comedy, but fortunately there's no danger of that -- no LOL noms here! In the end, it turns out that a Gunfighter vs. Graboid (that's what the monsters are called, for any of you not familiar with Tremors franchise lore) isn't much of a match. Beaten, bankrupt, and humiliated, Michael leaves Rejection in dejection and the others contemplate what to do with the remainder of their lives. But before they can flee, the monsters are upon them!

But wait! On the horizon! What's that? Michael, returned from Carson City, where he spent the money he retrieved from Black Hand Kelly's corpse (wait, wasn't that eaten?) on an arsenal! With heavy enough weaponry, even an untalented crew can defeat the monsters, rename Rejection to Perfection, and lay the groundwork for a bad movie franchise, continuity be damned!