A human colony near Gorn-claimed space whose resupply mission ended in a Gorn ambush on the USS Cayuga.
Parnassus Beta is the human colony that Captain Marie Batel's USS Cayuga is resupplying when the Gorn ambush it in Hegemony. The Enterprise finds the Cayuga destroyed and a Gorn device jamming communications and transporters, and Christopher Pike disobeys orders by leading a team to the surface.
They find Batel and other survivors, including engineer Montgomery Scott. After the jammer is destroyed, the Gorn capture several crew members and colonists, and in Hegemony, Part II the Enterprise pursues them into Gorn territory and rescues them.