A singing ranch foreman (Roy Rogers) and his friend (George “Gabby” Hayes) urge a chorus-girl heiress (Dale Evans) not to sell the property.

In 2020, after the colonization of the moon, the spaceships Vega, Sirius and Capella are launched from Lunar Station 7. They are to explore Venus under the command of Professor Hartman, but an asteroid collides and explodes Capella. The leader ship Vega stays orbiting and sends the astronauts Kern and Sherman with the robot John to the surface of Venus, but they have problems with communication with Dr. Marsha Evans in Vega.

Set in the early 1900s in the fictional Catfish Row section of Charleston, South Carolina, which serves as home to a black fishing community, the story focuses on the titular characters, crippled beggar Porgy, who travels about in a goat-drawn cart, and the drug-addicted Bess, who lives with stevedore Crown, the local bully.