On what is seemingly your typical pest-removal call, an animal conservationist and her ride-along boyfriend, Will, instead make a startling discovery: a species of sentient purple goo. They take it home for further observationonly to become hosts in a symbiotic relationship with what appears to be an extraterrestrial organism, leaving Will more similar to his girlfriend than he'd like. Nonetheless, a summer of slimy fun ensues, with Will getting the most out of his purple predicament.
But the both of them have to wonder: What does the goo ultimately want?