In a world where the fearsome Graboids have left their mark, the protagonist, Earl Bassett, has decided to leave behind his life of adventure and become a businessman. However, tranquility is short-lived, and he soon learns that these underground monsters have returned to wreak havoc, this time at an oil field in Mexico.
Drawn by the promise of a hefty paycheck, Earl joins a group of Graboid hunters who believe that handling the situation is simpler than it seems. But upon arriving at the site, he discovers that the Graboids have evolved and are no longer just voracious beasts: they have now developed the ability to move with greater agility and created a new, even more dangerous species, the Shriekers.
With the help of his tech-savvy companion, a couple of unlikely allies, and his wits, Earl must confront this new threat. As the situation grows increasingly chaotic and the Shriekers begin to reproduce rapidly, what was supposed to be just another job turns into a desperate struggle for survival. The combination of humor, action, and horror makes each encounter with these creatures a moment of tension, while Earl rediscovers his courage and ability to fight against fear, as well as to find purpose amidst the chaos.