Moon & Earth by Patty Jansen

The shocking conclusion to the Moonfire Trilogy.

Lana han Chevonian is one of the world’s brightest minds on the brink of making a huge discovery. There is only one problem: she is stuck as prisoner in the harem of the Aranian king. She could try to escape and run the risk of getting re-captured or getting killed on the very long and difficult road back home to Chevakia, or she could win the favour of the king, beg to be allowed to use the famed library and promise Arania credit for her work.

Meanwhile, war is about to break out between Aranian armies with icefire weapons and Chevakian armies wanting to wipe those weapons off the face of the earth.

Lana’s discovery turns the understanding about icefire on its head, but no one is listening. They’re on course to destroy everything that’s keeping the world alive.