History and specifics
Fomalhaut V was an arid desert planet with rocky outcroppings. In the 2260s decade, it served as the location of a massive underground military outpost for the Armies of Fomalhaut, who had stockpiled advanced weapons and armed spacecraft for a preemptive attack on the Federation. All they lacked were instructions on how to build a warp engine.
In 2267, the starship USS Enterprise was lured to Fomalhaut V by a false SOS distress signal that gave the impression the planet was populated by humans who were under attack by giant dinosaurs. Even though the ship's library computer reported no life on the planet, James T. Kirk was motivated by the potential harm to the citizens and beamed down with Spock and Leonard McCoy. They were immediately apprehended by soldiers of the Armies of Fomalhaut, who used their truth machine to coax the secrets of warp drive out of Spock.