The Nechani homeworld was a Delta Quadrant planet whose monks guarded a shrine to the ancestral spirits, where Kes was struck down and Janeway underwent a ritual to save her.
The planet appears in the third-season episode Sacred Ground. While the crew enjoy shore leave, Kes wanders into a cave shrine and is thrown back by an energy field, falling into a coma that the Doctor cannot treat.
The Nechisti monks hold that only the spirits can restore her. Janeway learns of a king who once petitioned them on behalf of his son, and she asks to go through the same ritual, treating it as a puzzle to be solved by science.
Her guide leads her through tests of endurance and a meeting with three sardonic elders. The data she gathers fails to help. Only when she sets aside her need for an explanation and carries Kes through the field does the young Ocampa recover.