Dexter Riley is a science student at Medfield College. By accident, he creates a liquid that can make things and people invisible. Before Dexter and his friends Debbie and Richard Schuyler can even enjoy their amazing find, the greedy businessman A.J. Arno plans to get his hands on it. As Dexter and his friends try to stop the bad guy Arno from robbing a bank with the invisibility spray, funny things happen.