Anton Bartok (Lee Richardson), the CEO of a research laboratory, acts as the self-appointed guardian of orphan Martin Brundle, whose father had been a researcher at the lab. Though Martin is scarcely five, he has the appearance of a 20-year-old (Eric Stoltz) because of mutant insectoid genes in his system. Martin grows up confined to the laboratory, unaware of his true nature, with only pretty scientist Beth Logan (Daphne Zuniga) to call a friend. Soon, the fly within begins to emerge