This is Stella Rimington's fifth novel featuring the clever and resourceful MI5 intelligence officer Liz Carlyle. While it's a stand alone novel, you'll probably enjoy it more if you've read some of her other books as many of the characters have made previous appearances.
At the start of the book, Liz Carlyle is transferred to Northern Ireland to take charge of MI5's agent runners division. Unbeknownst to her, the Director General is aware of her closeness to the recently widowed Charles Wetherby and wants to avert any potential inter-office romance. She expects to find that Northern Ireland is a backwater, but she soon discovers that there is a breakaway terrorist cell of former IRA members who want to continue the struggle by targeting policemen and members of MI5. When one of her colleagues comes under threat, she needs to quickly find answers.
As a thriller it's good but not outstanding. It's a well written and enjoyable read, but the tension never builds sufficiently to put it in the "can't put down" category. The villain is also devoid of any strong motivation or believability. On the other hand, what Rimington has going for her is credibility. As the former head of MI5, she knows the details that make the story feel authentic and knowing her pedigree definitely adds to the book. For example there is one early scene when an MI5 officer is meeting with his contact and the MI5 team are providing back up surveillance. Had I read this scene in another book, I might have thought: "well it wouldn't happen that way". Knowing Rimington's background, instead I could think: "oh, so that's how they'd do it". Fascinating.
I really like the way that Liz's character is developing and I thought this was one of Rimington's best yet. The romantic tension between Liz and Charles Wetherby is an ongoing sub-plot that didn't intrude on the main story but added a pleasing extra dimension. The ending wraps up the plot neatly, but leaves enough threads hanging to make it obvious that there will be another installment. I'm already looking forward to it.