16-year-old Yukito Kirihara lives with his 14-year-old sister Sana, who he treasures more than anyone else. But when an ogre shows up outside of his window looking for Sana (a shocking event in its own right), Yukito leaps to save her—and is killed. He's offered the promise of reincarnation by a mysterious woman, who gives him a character sheet in a mysterious book. But when Yukito sees Sana in th...