The Wall Between the Worlds

Cassidy Heights is still recovering from the freak snowstorm that wreaked so much havoc two months before, but Mikhal has his own problems. He's failing at pretty much everything, and the fact that he just punched his best friend in the face is just the icing on the cake. Now, geeky Sharna Devon has been assigned to tutor him, and Mikhal couldn't think of anything worse. Can't everyone just leave him alone? All he wants to do is to learn to play his guitar and overcome his stage fright so he can get rich, famous, and away from Cassidy Heights for good.
Mikhal's mum has other plans for him though. She's running a charity drive, and thinks it will assist Mikhal learn some responsibility to help out. Mikhal's friends, Jake and Keira, are also involved with the drive; but Mikhal is sure they're hiding something from him. When he discovers Jake's old mobile phone in one of the boxes dropped off for the drive, he and Sharna are dragged into the mystery. Jake and Keira's friend, Cari, is still trapped in the void between the worlds, and Mikhal's music is her only hope.
But there are mysterious forces working against them. What, exactly, does Mikhal's music teacher know about Shar, the City of Silver Light? And how can they stop the Guardians' latest attack which could destroy the entire Earth?