Invisible Girl

In this episode, Cordelia is campaigning to be crowned May Queen at Sunnydale High's next dance. Mitch, her prospective date for the dance, is clubbed in the locker room with a bat. The bat, however, seemed to move on its own, as if operated by some invisible person. Later, Cordelia's friend Harmony falls down the stairs, as if she tripped over her own feet. Harmony insists she was pushed, but no one saw anyone do it.

Everything points to an invisible person and Buffy finds out that someone has been living in the ceiling of Sunnydale High. The person is Marcie Ross, whom nobody remembers, not even Willow or Xander. But Marcie did go to Sunnydale High and she had a yearbook signed by most of the school. Even Willow and Xander signed it, with the phrase "Have a nice summer!" like everyone else.

Marcie had been turned invisible because everyone perceived her that way. Having been treated the worst by Cordelia and her friends, Marcie decides to take her revenge on her. She had devised a plan to kidnap Cordelia on The May Queen dance night and "give her a face that no one will ever forget."

Buffy manages to stop Marcie before she destroys Cordelia's face- though not before she slashes Cordelia's cheek. Marcie also practically killed Xander, Willow, and Giles by locking the in a room full of gas. Angel however saved them just in time.

While Buffy is untying Cordelia to FBI men come and take Marcie away. They take her to a special school with other people just like her. When Marcie is escorted into the room she receives a book. She opens to Chapter 11: Assassination and Infiltration. "Cool!" says an excited Marcie.