When the crew of the USS Enterprise recives a distress call from a nearby space station haversting the power of a binary star, Captian James T. Kirk and Spock take a shuttle to organize a rescue. There they encounter T'Mar a childhood friend of Spock's who reveals that the station was used to power up a device called the Helios Machine.
The Helios Machine has the power to speed of the terraforming of New Vulcan, but unwittingly the station was shut down for unknown reasons. After beaming to New Vulcan, Kirk and Spock meet with T'Mar's father Surok who explains the station's power from the base was lost after they were attacked by creatures - who called themselves the Gorn. The Gorn have arrived from a Rip opened in space from the space station caused by the Helios Machine. Kirk and Spock must now recover the device and stop the Gorn before they use the device and become unstoppable.