Atrium no Koibito 2

is the second volume of the Atrium no Koibito light novel series, written by Shinjiro Dobashi and Illustrated by Ryo Ueda. It was released under the Dengeki Bunko Imprint in September 2011.

Synopsis
The event game "Tactics Tokyo" was held in real Tokyo to promote the resumption of Sphere. Haruka, the director, is enthusiastic about participating in order to keep the circle alive. However, she left the circle with a mysterious word, "... don't give up on Tokyo." She even got into trouble of getting stuck in the game ...!? What is the fate of the SSS members who are bound by the "constraints" of the game in the real world?

(source: Dengeki Bunko Official Website - Translated)