Jani and the Great Pursuit — Eric Brown

Jani and her stalwart companions Lieutenant Alfie Littlebody and Anand Doshi find themselves chased from India, via Greece, to London by the British authorities, Russian spies and a Hindu priest -- who all want what Jani carries, the ventha-di: the key that will open the door to other worlds.

In London she attempts to rescue the imprisoned alien Mahran -- the only person who might help her save the Earth from the invasion of the merciless Zhell, the self-styled Masters of the Cosmos.

But will she escape London and reach Tibet before the forces of evil capture her -- and before she is betrayed by someone she considers loyal to her cause?