Frost Fever — Jonathan Moeller

In 2013, a gate to another world opened, and Elves used their magic to conquer Earth, crushing all resistance before them. Three hundred years after the Conquest, the exiled Elven High Queen rules an orderly but stagnant Earth, with humanity forced to fight in the High Queen's war against the traitors on the Elven homeworld. Nadia Moran doesn't care about that. She wants freedom, and she wants power. Unfortunately for her, she has little enough of either. To make matters worse, her baby brother Russell is dying of a rare magical disease, and the only one who can cure him is the cruel Elven archmage Morvilind. If that were not enough, Morvilind demands a steep price for his cures. Specifically, he wants Nadia to use her skill and magic to steal treasures for him, and this time he's sent Nadia to steal a priceless relic from the ambassador of the frost giants. And the frost giants never forget a grudge…