Dr. Grood has succeeded in winning control over the planet Ergro as the first step in his desired conquest of the Universe. Reporter Rex Barrow, his photographer Tim Johnson, Professor Edmund Dorn and his daughter Ella are all captured by Grood, who plans to make use of the professor's knowledge. With the help of the professor's inventions, Rex is able to free Ergro of Grood's domination, while Grood is sent on an endless voyage into space.