Well, I'll be dead in one year

In one year, humanity’s Savior Kamishiro Fuuka—will die. And yet one day, during our first meeting no less, she approached me. “Please go out with me.” As her boyfriend, it now became my duty to go through all sorts of events and plans she marked in her ‘Savior Notebook’ until the day she will die. Meeting in spring, checking out the summer fireworks, the cultural festival in fall, running away during the cold winter… The more memories we built together, the easier I realized—that she was still just a normal girl. So could I, the strongest shadow user and hunter of humanity’s evil, possibly save her before it’s too late?