Mel, Ludo and Wren are battling a new enemy - the sinister order of Ters, who have created storms over the city of Vlam. After a cry for help from a land in the Mirrorscape, the three friends go back into that strange and unpredictable world. They make new friends - and enemies - as they attempt to prevent the storms that threaten Vlam with a plague of demons. But the Ters and the terrifying demon-slayer Morg are sniffing at their heels. And it seems there is a traitor in their midst. The fate of more than one world is balanced on the tip of a brush...