Two dimwitted best friends, Bud and Doyle, accidentally stumble into an ecological experiment after mistaking the Bio-Dome—a controlled environment designed to model a self-sustaining ecosystem—for a mall. Once inside, they find themselves trapped with five scientists who are committed to spending a year in isolation to prove that a self-sustaining environment is possible. The duo's initial antics disrupt the carefully balanced habitat, creating immediate tension between them and the scientists. As the days progress, their presence threatens the stability of the entire experiment.

Despite their bumbling ways, Bud and Doyle begin to see the value of the project and make attempts to redeem themselves by contributing positively to the environment inside the Bio-Dome. However, their efforts to turn things around face numerous obstacles, both from their own incompetence and external pressures. As they navigate these challenges, they form unlikely bonds with the scientists and start to understand the broader implications of environmental responsibility. The movie evolves into a comedic yet poignant exploration of how even the most unlikely individuals can come to appreciate and fight for ecological preservation.