The Other Truth (W.I.T.C.H. Chapter Books #19)

Plagued by nightmares of Nerissa and doubts of thier own Powers, Will, Irma, Taranee, Cornelia and Haylin are growing weak. They need help. So when Hay Lin discovers and old letter to her grandmother she and Will are compelled to track down the writer for more information. The truth they uncover threatens Will's role as the kepper and forces the Guardians into a battle with Nerissa, in the realms of nightmares.