From publisher blurb:
You’ve witnessed the Hidden World, how it touches the landscape and cities of the United Kingdom. Now it is time to plunge deep into the heart of London and explore its diverse culture and historical strangeness.
Within these pages, meet the hidden who dwell in London’s forgotten places; an ancient vampire, fae courts and ghost realms, a statuesque dragon, the pig-headed lady, and many more beings both malevolent and benign, all intertwined with everyday people and places. But no matter what you do, do not breach the Pax Londinium over the Thames.
Pax Londinium is a sourcebook for the Liminal RPG and requires the core roleplaying book to play.