Episode Title:K is for Knowledge.Episode Description:W.I.T.C.H. gains new knowledge of their sorceress foe Nerissa, a former Guardian and one-time holder of the Heart of Kandrakar. Will discovers that her own elemental ability to generate white-blue lightning and bring electrical appliances to life is Quintesence, which contains the very essence of life itself within lightning. In the subplot, after Taranee's mother forbids her from seeing Nigel, Taranee decides to turn herself into a bad girl to rebel.