It all started with a "net cafe."

Toki Koichi is a soon-to-be father leading a complacent life. One day, he happens to stop by an internet café, and there he bumps into Kaho, his first love from his junior high school days. Having just fought with his wife, Koichi's heart is filled with his old feelings.

All of a sudden, a strange wave flows through the computers and cell phones in the net café, and the entire place blacks out, just before rain begins to pour outside. Unable to leave safely, both Koichi and Kaho stay overnight at the net café. The next morning, when they step outside, they find the world is completely different. Koichi is determined to find out why the entire café has transported him to a different world, and to return to his family in the original world.

As he fights against various fears and tries to solve the mystery, people start to disappear one after another. Can they all survive through such a crisis!? And what is the secret of his first love with Kaho!?