Mirrorworld Book 3: Stormwalker - Mirrorworld, #3

Ric Storm and his family manage to escape the chaos that engulfed Sydney and flee to Melbourne. But then, just as Ric is settling into a new life, he feels compelled to step through a swirling portal that mysteriously appeared on the lounge room wall. On the Magick Earth, the Queen of England calls on Raven - now knighted as "Sir Robin Frazer", to lead an expedition into the dark heart of India to combat the rising threat caused by the Thuggee - worshippers of the death-goddess Kali.
He is accompanied by his new squire, a handsome youth named Nathaniel. In Science Earth New York, Bobby and Jeanne are enjoying an evening stroll when an Eidolon portal suddenly appears nearby. Wanting to return to the world of adventure he loved so much. Bobby grabs Jeanne and jumps through. But before the furious Jeanne can chastise Bobby for his impulsiveness, they spot a horribly familiar figure who flees at the sight of them.
Has Stormwalker really returned? Bobby and Jeanne can't take any chances, and sail to England to warn Raven. Unfortunately the mercenary has already left on his mission, and they must pursue him half-way across the world to the subcontinent. However the Thuggee Cult is far more insidious than first thought, and has started to infiltrate the cities and towns. Its origins like deep underground, within a complex network of caves that thread through the entire Magick Earth.
To defeat the cult will not only require Raven and his team, but Bobby and Jeanne - and a mysterious duo driven by Destiny itself.