Kanchenjunga!

In a post-apocalyptic world of climate disaster and widespread human conflict, four mid age friends try to make their way from the ruins of England to the Great Southern Land (Australia) hoping to find safety. While in the foothills of the Himalayas, they find ancient scrolls of the Kanchen religious cult who believed human spirits could actually 'body jump' and increase their power to eventually dominant humankind.
Not knowing the full incredible content of the scrolls, nor who else seeks them, the friends helped by a former monk continue their way across a world of massive chaos and conflict. Along the way Jack, the main character, endures attacks of a powerfully spirit of unknown origin, which seeks to absorb his power and destroy him.
After weeks of travel and attacks by Nazis pirates, militant Islamic bands, warlord groups, crocodiles, Komodo dragons and female warriors known as the Amazons, among others, the group finally reach the flooded ruins of Melbourne. There among the wreckage of the former city they find 'The Dome' - a huge, inhabited fortress structure built on the top of a former massive sporting stadium. Here the group try to find sanctuary.
The Dome however presets its own dangers to the travellers. The insular dome community led by the remnants of a former high-tech company survives by building (AI) androids for internal security, external defence and trade with outside warring groups. Heavily armed and constantly under attack by warring gangs, remnants of former states and others, and ruled by a pseudo dictator; it has an alliance with other similarly militarised population centres in the region. But the dome society also faces its own deadly internal threats.
In this the first book of the series, the travellers with the help of others, find temporary shelter near the Dome. But now they need to gain entrance, and seek safety from the many external forces, both in human and spirit form, who seek to destroy them. And the group still need to learn the secrets of the Kanchen scrolls, and the deadly consequences of what such knowledge will bring to themselves, and those both within the dome and without.