A visionary astronomer, Dr. Janos Rukh (Boris Karloff) has invented a telescope that can look far out into deep space, into the Andromeda Galaxy, and photograph light rays that will show the Earth's past. He has theorized this as being possible for some years, much to his discredit among his fellow scientist-colleagues. Looking at the remote past on a planetarium-like dome in his lab, two of those ardently skeptical scientists, Dr. Benet (Bela Lugosi) and Sir Francis Stevens (Walter Kingsford), watch a large meteorite smash into the Earth a billion years ago in what is now the continent of Africa. Amazed by Rukh's demonstration, the pair invite him to go on an expedition to locate the impact site.