Adrian McKinty's series featuring Belfast detective Sean Duffy just keeps getting better and better with each entry. This is the fifth in the series and it opens when a young woman named Lily Bigelow is found dead in the courtyard of Carrickfergus Castle. Bigelow was a newbie journalist accompanying a group of Finnish businessmen on a visit to Northern Ireland. She entered the castle with a tour group late one afternoon and the next morning was found by the castle's caretaker at the base of a tower some one hundred feet high.
The caretaker swears that the castle was securely locked after the last visitors left, and it's clear that no one was able to get in or out of the castle overnight. In the morning, the only people there are the elderly caretaker and the victim. All the evidence suggests that Bigelow hid somewhere in the castle and then, sometime around midnight, climbed the tower and jumped off, committing suicide.
It's a classic locked room mystery and a thorough investigation makes it almost certain that there was no opportunity for any foul play. This cannot be a murder; it's suicide, plain and simple. Beyond that, Sean Duffy has already had one locked room murder in his career, and the chances of getting a second, he thinks, would be astronomical. Still, while everyone else is willing to write off the young woman's death as a suicide, Duffy continues to be troubled by niggling doubts, and when he continues to probe into the case the more puzzling and the more dangerous it becomes.
This series takes place during the time of the "Troubles" in Northern Ireland when Catholics and Protestants were battling each other and when most citizens and the authorities were caught in the middle of what amounted to a civil war. The previous entries in the series have all been set very squarely against this background. This book is set in 1987, and while the battle still rages, it plays much less of a role here. This is much more a straightforward crime novel, and Duffy is much less involved in the island's larger struggles than in the earlier books.
Sean Duffy continues to be one of the most appealing protagonists in crime fiction--funny, wise and personally vulnerable. I'm closing in on the end of the series--at least the end of the books that exist thus far, and I'm really dreading the moment when I will have to wait interminably for the next new Sean Duffy novel. This series was originally set to run for only three novels; I can only hope that it goes on for much, much longer than that.