The Empty Box and Zeroth Maria

is a Japanese light novel series written by Eiji Mikage, with illustrations by Tetsuo. The series began publication on January 10, 2009 by ASCII Media Works under their Dengeki Bunko publishing imprint.

The series has been licensed for an English release by Yen Press under their Yen On imprint.

Synopsis
Kazuki Hoshino values his everyday life above all else. He spends the days carefree with his friends at school, until the uneventful bliss suddenly comes to a halt with the transfer of the aloof beauty Aya Otonashi into his class and her cold, dramatic statement to him immediately upon arrival:

"I'm here to break you. This is the 13,118th time I've transferred. After so many occasions, I have to say that this is all starting to grate on me, which is why this time I'm spicing things up with a proper declaration of war."

And with those puzzling words, the ordinary days that Kazuki loved so dearly become a cycle of turmoil and fear—Aya's sudden appearance signals the unraveling of unseen mysteries surrounding Kazuki's seemingly normal friends, including the discovery of mysterious devices known as "boxes."