Drayan II was the home planet of the reclusive Drayans, whose sacred moon, the crysata, was the place their people travelled to at the end of their backwards-running lives.
Drayan II is the focus of the second-season episode Innocence. The Drayans have isolated themselves for decades after concluding that technology was eroding their spiritual values, and their first prefect, Alcia, makes a rare visit to Voyager when Janeway seeks to trade for polyferranide.
At the same time Tuvok's shuttle crashes on one of the planet's moons, which is holy ground. He finds three frightened children there, who vanish one by one in the night.
The truth emerges only at the end: Drayans age in reverse, and the children are elders who have come to the moon to die. Tuvok stays with the last of them, Tressa, in her final hours.