A faithful adaptation of the Edgar Allan Poe story about subjectivity, in which a man believes he sees a hideous monster approaching his home. He actually is viewing a sphinx moth outside his window.

An astronomer and a cryptographer uncover a series of ancient tunnels, unwittingly unleashing a deadly Sphinx. In order to trap the Sphinx back in its tomb and stop impending destruction, our explorers must solve a series of complicated and possibly deadly riddles.