The novella is an exploration of the possibilities that humans, with the proper training, have the potential to make use of a wide range of telepathic and telekinetic abilities.
The story begins with the rediscovery of innate human psychic powers by three friends, all from a California university: Joan a grad student; Ben, a surgeon and instructor at the medical school; and Phil a psychology professor.
Bierce is revealed as one of a group of individuals who have developed their telepathic powers and all now live in secrecy on Mount Shasta in an elaborate cave structure.
The caves are over 100 meters long with generous side rooms including a library filled with powerful ancient knowledge.
Unlike Luke Skywalker whose talent with The Force seems to be a family trait, the abilities suggested in Lost Legacy are supposed to be in every human, needing only instruction and practice to master.
After rescue by Bierce the three main characters are introduced to the residents of the cave and after a few weeks are invited to stay and receive further training.