Amy's sixteenth birthday party is ruined when her two best friends start fighting and storm out. Her day only gets worse when things begin exploding around her. A foul-tempered spirit has awoken in her mind, and it tells her she's the reincarnated host of the Shield, born to defend against the Sword.

​The Shield wants to protect all life, and the Sword wants to end it, yearning to send the universe back into the quiet of nothingness. The two spirits have been locked in a cycle of battle, death, and rebirth for millennia. But Amy isn't a violent person-she can't even eat meat! She just wants to do well in school to get into her dream college, not fight someone potentially to the death.

Connor has spent his entire life diligently training to be the Sword's perfect host and never questioned his fate-until meeting Amy. He's only ever wanted to live up to his family's expectations, is even willing to die in battle, but Amy slowly opens his eyes to a different path and now questions are all he has.

​Starting out as enemies, Amy and Connor slowly become friends and grow into more. Trapped by destiny, they must decide between fighting for the fate of the universe or fighting for themselves.