Axis (the tree world)'s life is in danger. Its sap has almost all run out and its people's efforts to implore the gods are in vain. Kaena has strange visions and she is convinced that Axis is calling her for help. Kaena, a young girl with the heart of a rebel, will defy her tribe's taboos and the Grand-Priest's supreme authority. And so begins her dangerous journey to Axis's deepest roots. She is helped by a mysterious creature from another world. The frightening truth that Kaena will discover at the end of her quest will profoundly change her forever.