Its good, but the mystery is not well explained. Also, there's a big loop hole in this one for me. I mean where did that come from, how it comeback alive again, did they solve this mystery or they all die? I mean its kind of hard if some of them will die, since the main character does not get affected by that disease so it is hard to come up with a conclusion. But the extra is literally good, short but well explained and written
Gyo