In the case of Mai Minase.
The episode starts when Tokuoka was kicked out of CC Corp. Mai and her boyfriend, Tomonari Kasumi (known to The World as Sieg), are taken to a hospital due to both of them collapsing while playing a MMORPG called The World. Despite Mai waking up shortly after arriving at the hospital, Tomonari remains in a coma. For this, Mai is the object of rumors, especially when the clubhouse (known as G-study) is closed after the incident. It is soon revealed that she heard a certain sound (which is also present at important points in .hack//Sign) shortly before collapsing, and she later discovers that it is A in C major, which is used to tune instruments, including her violin. It was this sound that enabled her to wake up, and it was the first sound she made when she did. She meets Junichiro Tokuoka, and although she distrusts him at the beginning, as they investigate into Tomonari's coma, they soon become allies, if not friends. The investigation itself starts with Tokuoka accessing Tomonari's (Sieg's) account on The World, with Mai providing the password. Tokuoka accidentally opens the e-mail, and discovers that two users, Yukichin and Kyo, are close with Tomonari and have been harassing him with e-mails regarding his absence...