Yoimachi Meme 
Riverbed Projector 4 [EPUB ebook] 

With Endou safely returned to the real world, Sumida (or Hotori, as those in Kawazoko know her) goes back to her old double life of school in the real world and strange happenings in the otherworld, with no humans she meets — including Endou, now — ever able to really remember her. Her brother hears her often talking to someone on the phone, but who could she be talking to? He confronts Hotori, but perhaps not in time to avert disaster. Something in the past of the Sumidagawa family is about to come to light.