The Summer War (en Inglés) - Naomi Novik

Celia discovers her talent for magic on the day her beloved oldest brother Argent leaves home. Furious at being left behind, she lashes out, not realising her childish, angry words will suddenly become imbued with the power of prophecy, dooming him to a life without love.

While Argent wanders the world, forced to seek only fame and glory instead of the love and belonging he truly desires, Celia attempts to undo the curse. Yet she cannot find the solution – until she learns the truth about the centuries-old war between her people and the summerlings, the immortal beings holding a relentless grudge against their mortal neighbours.

With the aid of her unwanted middle brother, Celia may be able to undo her eldest brother’s curse and heal the lands so long torn apart by the Summer War. But what price will she have to pay?