Serial Experiments Lain is a cult-classic cyberpunk anime series released in 1998, directed by Ryutaro Nakamura and written by Chiaki J. Konaka.
The story follows Lain Iwakura, an introverted schoolgirl who becomes obsessed with the Wired (a global, highly advanced version of the internet). This obsession begins after she and her classmates receive an email from a dead peer, Chisa Yomoda, who claims she didn't die but simply abandoned her physical body to live inside the Wired, where God resides. As Lain upgrades her computer terminal (known as a NAVI), the boundaries between reality and the virtual world begin to collapse.
The central experiment of the series is orchestrated by Masami Eiri, a scientist who modified the Wired's protocol (Protocol 7) to link the collective unconscious of humanity.