Kimi ga Shine: Tasuuketsu Death Game

Joe Tazuna has always been the most selfless person Sara Chidouin has ever known, someone she could count on to take a bullet for her. But that trust is put to the test when they wake up restrained to some strange tables and discover Joe holds a key that can set only one of them free. Thus begins a mysterious and sadistic game that will require all of their wits and faith in each other to survive…!
(Source: Yen Press)