The hidden twin

"For eighteen years a girl with no name, a Redwing, has been hidden away in a small attic room within a city of hissing pipes and curving temples perched on the side of the great volcano, Mol, while her sister, Jey-identical except for her eyes-has lived her life in public as an only child. Their father had hoped the hidden girl would one day grow up to be a normal human girl and not the wicked creature mythology has promised, so he secretly spar...