'Out Of Sight, Out Of Mind' (a.k.a. 'Invisible Girl') Story Code '4V11' by Joss Whedon (story) Ashley Gable and Thom A. Swyden (teleplay)

At Sunnydale High, Cordelia is running for the title of May Queen. However, her boyfriend Mitch and her friend Harmony both fall prey to attacks from a seemingly invisible force; meanwhile Buffy hears laughing, but cannot track down its source. She and Willow link the attacks to a missing student, Marcie Ross, whom no one can remember. Buffy tracks Marcie down to her lair inside the school’s air ducts, where she finds the girl’s yearbook; from the standard entries that fellow students have written to her, it she realises that the girl had no friends, and it appears that she was neglected so much that she actually became invisible. Cordelia believes that she is to be Marcie's next target, and asks Buffy to help her. Marcie sets a trap for Giles, Willow and Xander in the school basement where there is a gas leak, but luckily Angel saves them in the nick of time. However, Marcie captures Buffy and Cordelia, and when the two girls eventually come to in ‘The Bronze’, they find themselves tied to chairs. They realise that Marcie has gone mad during her isolation, and now wants to disfigure Cordelia, whom she blames for her turning invisible; it was Cordelia and her clique of friends who always ignored Marcie at school. Buffy manages to break free, and using her powers as the Slayer she is able to overcome the difficulty of battling an opponent that she cannot see. Two FBI agents then arrive and take Marcie into custody, telling Buffy and Cordelia to forget what has happened. Cordelia thanks Buffy and her friends for their help, but still refuses to acknowledge them publicly as it will tarnish her image!

Sarah Michelle Gellar (Buffy Summers), Nicholas Brendon (Xander Harris), Alyson Hannigan (Willow Rosenberg), Charisma Carpenter (Cordelia Chase), Anthony Stewart Head (Rupert Giles), David Boreanaz (Angel), Armin Shimerman (Principal Snyder), Clea DuVall (Marcie Ross), Ryan Bittle (Mitch), Denise Dowse (Ms. Miller), John Knight (Bud 1), Mercedes McNab (Harmony), Mark Phelan (Agent Doyle), Skip Stellrecht (Agent Manetti), Julie Fulton (FBI teacher)
Directed by Reza Badiyi

TX (US): 19th May 1997
TX (UK - Sky One): 14th March 1998
TX (UK - BBC 2): 17th March 1999

Notes:
*Featuring Buffy, Xander, Willow, Giles, Cordelia and Angel