U is for Undivided

U is for Undivided is the 21st episode of the second season and the 47th episode overall  of W.I.T.C.H. It first aired November 11, 2006.

Summary
It is revealed that Lillian is actually the Heart of Earth, its source of magic, and the Guardians have to protect her, while Cornelia attempts to gain her sister's trust.

Lillian accidentally turns her cat into a familiar and creates a glamour zone around her home, based on Cornelia's bedtime story. The guardians clean up the mess, and Matt, Mr. Huggles and Napoleon, Lillian's pet cat, become the Regents of Earth.

In the B-story, Cornelia starts being happy for her sister.

Trivia

 * It is revealed that Lillian is the Heart of Earth and why Cornelia was chosen to be the Earth Guardian.
 * The episode's writer is Cary Bates, best known to comic fans for his fourteen year stint as writer of the Flash, as well as writing Superman, Action Comics, Justice League of America, and Captain Atom (with Greg Weisman)