this anime is really good until episode 12.. the last episode just didn't have that impact because of happy ending probably. and the cat girl which should be the main villain (i think) didn't do anything, she literally doing nothing LOL the music is great, character development is good, story is pretty good too, and the animation is great! it just the last episode that almost didn't have any impact and kinda ruin it. i mean i'm in tears when oto leave and adashino just reduce to dust then the scene where oto finally say thank you to sumireko. i'm fine with happy ending like this, butthat doesn't mean you can just make adashino spawn on a "anomalies" bookstore LOL

overall it's 7/10 from me, it'll be a 8/10 if the last episode didn't ruin it..
time to read the manga i guess