Prince of Hazel and Oak
Shadowmagic #2
John Lenahan (2011)

Having returned to the real world from Tir Na Nog at the end of the last book, Conor finds himself arrested for the murder of his father. When he explains to the cops that his dad is safe they think he is a nutcase. But being rescued by Celtic warriors on horseback brings back the policeman with him.

This seems to be a device that isn’t needed. As a result the story gets bogged down introducing a new character, when it should be taking off. And after a third of the book it never takes off, so I did.