A few years after Seth Brundle, or BrundleFly, met his demise by Veronica's shotgun, she dies after giving birth to its son, Martin. Seth's employer, Bartok (Lee Richardson), adopts Martin, only to have the genes so he can use them to create a super army of genetic flys. A few years later, Martin (Eric Stoltz) is fully grown, even though he is five, and the fly genes start to wake up and make him just like dear, dead dad. With the help of his girlfriend, Beth (Daphne Zuniga), they go to wherever they can find help. But Bartok finds them, brings them back, but before Martin finishes his transformation into MartinFly.