One of three Denobulan scientists studying a cave system on Xantoras whom Enterprise is sent to bring out when the planet's new government expels all off-worlders.
Trevix appears in The Breach. He, Yolen and Zepht are deep inside the caverns of Xantoras when a militant faction takes power and gives foreigners three days to leave. The Denobulan authorities ask Phlox's ship to collect them.
Tucker, Reed and Mayweather climb down after the geologists, a descent that leaves Mayweather with a broken leg. When they finally find the team, the scientists are absorbed in their work and unwilling to abandon months of research on the word of strangers.
It takes a good deal of argument, and Tucker's temper, to get them moving, and the climb back is slowed by rock falls as the deadline runs out. Enterprise leaves orbit with all three aboard.