Luna has lived alone at the base of the mountain for as long as she can remember. Her days follow the same pattern: collecting gems, returning to the river for water. Then the river slows to nearly nothing, and a new deer moves into the area. There is not enough water for both of them, and not enough for survival. After a strange dream involving powers she does not yet understand, Luna sets out to discover what has interrupted the river. Along the way, new animal companions join her, and the dangers of the wild are not optional.