//signal.

The story is set in the near future, where the old human race lives in the real world. They have been largely divided into the new human race, who have abandoned the real world and live in a world of computer technology. The story begins one day, when Lain receives an email and a file. Why did people lose their connections? How can they be reconnected? The protagonist, Lain Iwakura, searches for the truth while interacting with various people she was involved with in the past.