Sister Fidelma is undergoing something of a crisis of faith, abandoning her role as a religieuse to focus on her role as an investigator, something that has driven a wedge between her and her husband Eadulf. But they both find themselves heading towards the abbey of Lios Mor to investigate a sinister murder.

A scholar, Brother Donnchad has returned to the abbey from Rome and has become a recluse. He has made an important discovery that could affect Christianity itself, but it seems that somebody does not want him to reveal it. Donnchad is found murdered, locked inside his cell – but the only key to the cell is found on the body…

With war threatening to break out between the clans that neighbour the abbey, it seems that someone is playing a very dangerous game with the highest of stakes…

Another trip to Ireland, AD 670, and it’s business as usual for Fidelma. Her marriage is in trouble, which gives Eadulf a chance to spell out just how objectionable she can be at times – too little, too late, perhaps – but as ever, this doesn’t get in the way of Peter Tremayne’s classic-style murder mystery.

What some people seem to have an issue with – indeed, there has been the odd occasion where it’s bothered me too – is the occasional lapse into theological history and philosophy, but here, it’s much less intrusive, and on top of that, it’s fairly essential to the motivation for the murder.

It’s a fun and intriguing read with well-drawn and distinctive suspects – not necessarily an easy task when most of them are monks from the same abbey – and the plot is nicely complex while still having a clear indication of the murderer. It has to be said that I can imagine that some may be disappointed with the solution to the locked room, as it’s pretty straightforward, but it works perfectly well and is fairly clued.

The nineteenth Fidelma novel, it’s something of a return to top form after The Dove Of Death. Some people might be put off by the religious philosophy, but it’s such a pleasure to read an historical mystery with a genuine historical motive. Highly Recommended.