After the fall of civilization, a hierarchical society was born where blood determines everything. The rich steal both the blood and lifespans of the poor, rejoicing in their eternal lives. Nagi is a commoner doomed to an early death, while Saya is a royal gifted with eternal youth. When their unlikely paths cross in a twist of fate, their innocent love sets the gears in motion to tear down the walls of a society built upon tremendous inequality and discrimination.