Arrogant scientist Sebastian Caine has developed a serum for the military that can make a subject invisible. His team includes ex-girlfriend Linda McKay, Matt Kensington, Sarah, Janice, Carter, and Frank. The team succeeds in reversing the procedure, returning an invisible gorilla to visibility. Sebastian becomes infatuated with Linda again but, unbeknownst to him, she has become involved with Matt.
Instead of reporting his success to the military, Sebastian lies to an oversight committee which includes his mentor Howard Kramer, telling them he is close but needs more time. He convinces part of the team to go right into human testing without military authorization, keeping the rest in the dark. The procedure is successful and Sebastian turns completely invisible. He enjoys sneaking around the lab in order to scare and play pranks on his fellow co-workers, one of which involves molesting Sarah. The team becomes concerned that Sebastian is taking it too far. The procedure to return him to visibility fails and he is almost killed.
