Used book – The Power of Friendship, Disney, Elisabeth Lenhard

Things are getting complicated for the W.I.T.C.H. Besides their frequent arguments, Cornelia still refuses to see her friends and Will has to move. But the five Guardians must prevent their group from breaking up at all costs. The survival of the worlds and their mission as Guardians depends on it! Indeed, Luba, Guardian of the Aura drops, is willing to do anything to convince the Oracle that he made a terrible mistake in choosing them...