The Sapphire Portal is the shattering fourth and final instalment of Ian Irvine's best-selling fantasy series The Gates of Good and Evil. 

The Sapphire Portal is ready, and the Merdrun are bringing their long-hidden women and children through. There’s no turning back now. But what is the true purpose of the portal? Is it a horrific new weapon to cleanse Santhenar of all four human species, so the Merdrun can take it for their own world? Only their arch-sorcerer, the magiz, knows. 

Karan and her allies embark on the most desperate plan of all, to find out what the Sapphire Portal is really for and subvert its purpose, before it’s too late for Santhenar. But it’s the most heavily defended site in the world, and not even an army could get near, so what can a slave and a 10-year-old girl hope to do?