AllMovie

This youth-oriented sci-fi adventure concerns four astronauts who travel to the Planet of Eternal Night. A young scientist named Daniel (Guillermo Murray) and his girlfriend Silvia (Adriana Roel) lead the mission, and take along a boxer and his manager for comic relief. The planet's occupants live underground because the surface is blindingly bright and hot, and they are ruled by The Protector (Jose Galvez), who wants to blow up the Earth with a death ray. The usual cartoonish adventures ensue, until Daniel and Silvia manage to save the day. Director Alfredo B. Crevenna's film looks like a 1930s Flash Gordon serial rather than a product of the '60s, but it was popular enough to bring the characters back for a sequel, El Planeta de los Mujeres Invasoras.