In the first chapter she says her dad bought a bomb shelter in 1999. So how long has he owned this house? Is it his dad's (her grandpa's) house and he just never moved out and got married? How old is she? How old is he? It feels like this is less "Japan 2035" and more that this is an alternate version of 2019 with, I'm not going to say better, but different technology than what we had.