Jean-Paul is a Frenchman who yearns to live in communist Czechoslovakia. His wish is granted when, mistaken as a masseur of a French boating team, he manages to elude the democratic authorities long enough to scamper over the Czech border.
A man is sentenced to prison for a murder he did not commit. Thanks to a serum invented by his brother, he manages to become invisible and escape from prison in order to prove his innocence, while his brother works feverishly to find an antidote.
Teenagers from a small town and their high school science teacher join forces to battle a giant mutant spider, living in a cave nearby and getting hungry.