The White Horse Trick (The New Policeman #3)

It is the latter part of the 21st century, and dramatic climate change has made life in Ireland almost impossible. Meanwhile, Tir na n'Og is faced with a refugee problem, and the king of the fairies is not happy about it. When it is revealed that the warlord behind the problem is a member of the Liddy family, JJ is sent to sort him out.