Kimi no Tame ni, Onee-chan ga Minna Koroshite Ageru: Project Dia Horizon

What is beyond the farthest horizon? The final sea. Death... Hope...Freedom... The girl who carried the furthest secret by birth. For the girl... dreaming and living freely was not allowed. A word like freedom was nothing but longing. She was made to live in a closed and narrow world. Even dying and living were chosen by someone. So I thought. If it's that we were given only poor scenarios from God, I want to share death with you, not someone. I want to give half my life to her. Even if it was sharing death. That's why I'll walk with you. Beyond that horizon. We met and shared two lives with one death....