Darksong

These are the signs by which the Unraveller shall be known: Half-blind yet seeing all, marked by visioning yet without Darkfall mark, who lives yet sings the death song, who is born yet is not of the Song of Making, who is gifted from the Great Waters, who is crowned in bright flame . . . Legendsong of the Unykorn. After crossing to the troubled world of Keltor, Ember learns that her twin sister also crossed, and is in great danger. She must find Glynn and warn her before it is too late. Summary from isobellecarmody.net.au