Fourth's name is Kurusu Keigo.
(Gasai is Second.)
Amano and Gasai go to an amusement park together... to lure out the other Diary keepers. Yeah, that's it.
Ninth escapes, but is captured by another Diary keeper.
Amano opens a locked door at Gasai's house and is shocked.
Why does she have dead bodies (mummies?) in her spare room?
Amano flees, but it's not like he can really get away. She knows everything he does, after all.
His opening of this door changes everyone's future.