Scientist Sebastian Caine (Bacon) has developed a serum that can make a subject invisible. His team of scientists, which includes ex-girlfriend Linda McKay (Shue) and Matt Kensington (Brolin), eventually enable the serum to work on a female gorilla and restore the animal to visibility. Sebastian once again becomes obsessed with Linda while unbeknownst to him, she has become involved with Matt. Instead of reporting his success to the military, Sebastian lies to the oversight committee, which includes his mentor Howard Kramer (Devane), convincing his team to go right into human testing. The procedure is performed on Sebastian himself. Despite the pain he undergoes, it is successful and Sebastian turns completely invisible. He then enjoys sneaking around the lab in order to scare and play pranks on his fellow co-workers. They become a little concerned that he is taking it too far. After three days, however, he is unable to revert to visibility.