Multiplex: Kanojo to Boku no Komitta Hibi

is a Japanese light novel series written by Tosei Tamura, with illustrations by Himeko Korojuki. The series began publication on August 10, 2007 by ASCII Media Works under their Dengeki Bunko publishing imprint.

Synopsis
It was supposed to be just a game. But she really exists ... Fictitious x reality. The dangerous game is about to begin.