AustLit

'The ferocious warrior race, the Merdrun, have finally succeeded in invading the beautiful world of Santhenar, in the culmination of a plan they’ve been working on for ten thousand years. But they have only fifty-five days to build the Sapphire Portal, the greatest tower in the history of the Three Worlds, and put their dreadful plan into effect. 

'Karan, Llian and their dubious and untrusting allies have only fifty-five days to destroy the reborn  summon stone that gives the Merdrun their power. Fifty-five days to develop their daughter Sulien’s magical gift and unlock the hidden memory that could reveal the Merdrun’s one fatal weakness. Fifty-five days to save her life.

'But Sulien has been abducted, along with dozens of other gifted children and a hundred thousand adults, all enslaved to build the mighty portal in time. To save her life, Karan faces the most difficult choice of all – going into the enemy camp and becoming a helpless slave herself.' (Publication summary)