W.I.T.C.H. is about five girls, known as guardians, who were given the power to control the elements. Each one can control a different element, Will controls energy, Irma controls water, Taranee controls fire, Cornelia controls earth, and Hay Lin controls air. They were given these powers by the Oracle of Kandrakar to protect the veil, a special barrier that was created to keep the Metaworld and Earth seperate. The girls' task was to seal the twelve portals that had opened in the veil to protect Earth from the evil in the Metaworld. Meridian, part of the Metaworld, was ruled by an evil prince named Phobos whose goal was to gain more power. With the help of his servant, Cedric, he was able to find his sister, the long lost princess, Elyon, who was brought to Earth by her soldiers in order to protect her from Phobos. After finding her, he attempted to steal her powers, but the girls stopped him and he was sentenced to live for eternity in the Tower of Mists, Kandrakar's prison. Elyon then became the queen of Meridian and after that, there was no need for the veil anymore. So the Oracle lifted the veil between the worlds. The girls didn't think they had anything more to do and tried to focus on living a normal life. Little did they know that there would many more tasks in store for them.
Were there guardians before the girls of W.I.T.C.H.?
Yes, and Hay Lin's grandmother was a member of the group. The other five girls were Nerissa, Cassidy, Halinor, Kadma, and Yan Lin. The group however was not as solid as W.I.T.C.H. and fell apart. The Oracle could tell that Nerissa was being corrupted by the Heart of Kandrakar, so he took it away from her and gave it to the only one he felt was capable of handling it, Cassidy. However, in a power hungry and jealous rage, Nerissa killed Cassidy. Cassidy's death made Halinor and Kadma question the Oracle's decisions because he knew what could have happened had he given the Heart to Cassidy, yet he did so anyway. Halinor and Kadma were banished from Kandrakar for questioning him. Yan Lin remained loyal though and after her death on Earth, she became a member of the congregation of Kandrakar. As for Nerissa, her actions earned her what was supposed to be an eternity in captivity on Mount Thanos.