When pirates attack a cargo ship off the Somalian coast and one of them is found to be a British-born Pakistani, alarm bells start ringing at London's Thames House. MI5 Intelligence Officer Liz Carlyle is brought in to establish how and why a young British Muslim could go missing from his well-to-do family in Birmingham and end up on board a pirate skiff in the Indian Ocean, armed with a Kalashnikov. Meanwhile, the owner of the charitable NGO that leased the ship suspects that his fleet is being deliberately targeted. But why would pirates be interested in charitable supplies? And how do they know the exact details of his ships' cargo and routes? When an undercover operative connected to the case turns up dead in Athens it looks like piracy may be the least of the Service's problems. Now Liz, with the help of Peggy Kinsolving, Dave Armstrong, and the rest of her unit, attempts to unravel the connections between Pakistan, Greece and Somalia. She'll have to rely on their wits-and the judicious use of force-to get to the truth. And she doesn't have long, as trouble is brewing closer to home: the kind of explosive trouble that MI5 could do without

Our concern – and we've communicated this over the weekend to all stations – is that the opposition may be about to deploy an invisible.'An invisible is CIA speak for the ultimate intelligence nightmare: the terrorist who, because he or she is an ethnic native of the target country, can cross its borders unchecked, move around that country unquestioned and infiltrate its institutions with ease. An invisible on mainland Britain was the worst possible news. For Liz Carlyle, an MI5 Intelligence officer, this report from MI6 marks the start of an operation which will test her to the limit and put her own life in jeopardy. As she sifts the incoming evidence and gets reports from her agents she realizes there is an immanent terrorist threat. But who or what is the target? And who and where is the invisible? Time is of the essence in this desperate search and it becomes clear that it is Liz's intuitive skills, her ability to get inside her enemy's head, which offer the only hope of averting disaster. In this terrifying and tautly drawn debut thriller Stella Rimington takes us to the heart of the Intelligence world. It is a place she is uniquely qualified to describe