A planet whose government was overthrown by a militant faction in 2153, forcing Enterprise to retrieve three Denobulan geologists working deep inside its extensive cave system.
Xantoras is a planet seen in the Enterprise episode The Breach. In 2153 a militant faction seizes power there and orders every off-worlder to leave within days, on pain of imprisonment.
The Denobulan government asks Enterprise to collect three of its geologists, who are studying a cave network far underground and cannot be reached by communicator. Tucker, Reed and Mayweather climb down after them; Mayweather breaks his leg in a fall, and the scientists at first refuse to abandon their work.
The team gets everyone out just as the new authorities begin firing on departing ships. The same episode follows Phlox's struggle to treat an Antaran patient who refuses help from a Denobulan.