Beyond the Boundary is set in a world where supernatural beings known as "youmu" are hunted by Spirit World Warriors. Akihito Kanbara is an immortal half youmu, who, despite the dangers of his existence, continues to live a peaceful life. That all changes when Akihito meets Mirai Kuriyama, a Spirit World Warrior with a seemingly cold personality.
As the two form an unlikely bond, they begin to uncover secrets that could change their lives forever. With danger lurking around every corner, will they be able to find out what lies beyond the boundary?
