Kimi no Tame ni, Oneechan ga Minna Koroshiteageru: Project Dia Horizon
君のために、お姉ちゃんがみんな殺してあげる～プロジェクト ディアホライゾン～
A girl is bound by a secret she was born with, never allowed to dream or live freely. Her existence is confined to a restricted world, where even life and death are decided by others. Freedom is a distant longing, not a reality. Convinced that life has dealt them only bleak fates, she wishes to share death with one person rather than anyone else. She wants to give half her life to this person, even if it means sharing death. Because of this, she decides to walk forward with them, beyond the farthest horizon. They meet and share two lives through one death.