Illusions and Lies (W.I.T.C.H. Chapter Books, #6) by Elizabeth Lenhard

Condition: great

Will, Irma, Taranee, Cornelia, and Hay Lin know all about illusions. Since they discovered their powers as Guardians of the Veil, they have kept their secret hidden. While the girls use deception only to protect people, Cedric uses lies to turn the girls against one another.

It is not until Will's life is put in danger that the other Guardians discover that the one thing that is not an illusion is true friendship.