A Seven-Day Pact with the Grim Reaper

I'm just an ordinary person, but one day a girl who called herself the Grim Reaper appeared before me.

That day, she declared that I was going to die, and that I had only seven days left to live...

I don't want to die like this. I learned there was only one way to save myself: find someone to take my place.

I want to live. I don't want my life to end like this, so I set out to search... But what will happen in the end...?