The Thirteen Curses (13 Treasures, Band 2)

The fairies stole her brother . . .
. . . and now Red is trapped. In the dangerous fairy realm, she strikes a bargain. Her brother will be returned, but only if she can complete a perilous magical quest in the human world. If she fails, she will lose him - and her own freedom - for ever.
With the help of Tanya and Fabian, Red's desperate task begins - but a shocking discovery turns it into a race against time.
And even if the friends succeed, will the fairies keep their promise?