A carefree nurse, Claire, and her friend, a fashion model named Martine, are growing weary of the hustle and bustle of New York City life. Seeking tranquility and a break from their hectic careers, they decide to spend their summer at Camp Sunshine, a serene nature retreat in the countryside. Claire's boyfriend, a scientist named Luther, works at a nearby laboratory that happens to be conducting experiments on growth hormones. His latest concoction shows promising results in increasing animal size, but it's not yet ready for practical application. When Luther's curious rat accidentally consumes the untested serum, the consequences are unexpectedly alarming.

In the meantime, Claire and Martine have settled into the idyllic camp, basking under the sun and embracing outdoor activities alongside the eclectic assortment of campers. The peace is shattered when Luther's growth hormone inadvertently finds its way into the camp's water supply. As the campers remain oblivious to the scientific misfire, nature itself begins to react in bizarre and exaggerated ways. The tranquility of Camp Sunshine becomes overshadowed by odd occurrences, leading to a tension-filled atmosphere among the campers as they try to figure out the cause of the mysterious changes unfolding around them.