一名科學家製造出「電子傳送艙」，能將物體重組後即時傳送他處，經多次成功試驗後，他決定用自己做實驗。沒想到，傳送過程中，一隻小蒼蠅意外飛進機器裡......。

這部拍攝於1989年版的《變蠅人2》是1986年版《變蠅人》的續集，影片承接第一集母親維尼卡懷上賽斯孩子的伏筆，當她產下一枚蠅蛹時被當場嚇死。當局的科研機關巴托工業園收養了蒼蠅之子馬丁·布朗多（艾瑞克·斯托羅茲 Eric Stoltz飾），由巴托工業的老總巴托先生（約翰·蓋茲 John Getz飾）撫養。巴托先生密切監視著馬丁的一舉一動，表面上把馬丁視如己出，實則卻把他當作研究物件，暗地裡用攝像機記錄下他所有的生活過程，讓馬丁研究他父親生前的時空傳送裝置。馬丁看上去英俊帥氣，無異于常人，除了的驚人的生長速度和超人的天資才能。不久，馬丁就與美麗的貝斯·洛根（達芙妮·祖尼加 Daphne Zuniga飾）墜入愛河。可隱藏在馬丁體內的變異染色體突然蘇醒，等待馬丁的是變成下一個“蒼蠅人”的恐怖噩耗。

Industrialist François Delambre is called late at night by his sister-in-law, Helene Delambre, who tells him that she has just killed her husband, André. Reluctant at first, she eventually explains to the police that André invented a matter transportation apparatus and, while experimenting on himself, a fly entered the chamber during the matter transference.

Two dimwitted buddies hatch a money-making scheme after discovering an overgrown fly in the boot of a car.

Fifteen years after his father's experiments with matter transmission fail, Philippe Delambre and his uncle François attempt to create a matter transmission device on their own. However, their experiments have disastrous results, turning Philippe into a horrible half-man, half-fly creature.

While filming in Transylvania, a crew unearths celluloid images of a woman’s murder and unleashes the wrath of evil spirits.

The flower fairies help a little girl named Mary to thwart germs.