Days of Blood and Starlight is the sequel to Taylor’s Daughter of Smoke & Bone which follows a blue-haired girl named Karou one a quest to find out who she really is.

From EW (official synopsis):

In this stunning sequel to Daughter of Smoke and Bone, Karou must come to terms with who and what she is, and how far she’ll go to avenge her people. Filled with heartbreak and beauty, mysteries and secrets, new characters and old favorites, Days of Blood and Starlight brings the richness, color and intensity of the first book to a brand new canvas.