Yuuki, an 18-year-old in the year 22XX, carries the legacy of two distinct extraterrestrial tribes. His father originates from the "hero" tribe, while his mother belonged to a tribe gifted with plant manipulation abilities – a people believed eradicated by the planet's accelerated mechanization. On his 18th birthday, Yuuki learns of this dual heritage and the likely destruction of his mother's people through technological advancement.

He inherits special powers from both bloodlines: undefined capabilities from his father's "hero" tribe and the specific ability to control and influence plant life from his mother's tribe. This unique genetic combination makes him a hybrid.

Yuuki's core conflict stems from reconciling these dual legacies. He grapples with uncertainty over where his loyalties belong and which side to support with his combined powers. The suppressed lineage of his mother's plant-controlling tribe, nearly wiped out by mechanization, contrasts with the path represented by his father's tribe. This internal dilemma defines his character, forcing a choice between supporting the forces of mechanization or the surviving remnants of his mother's tribe.