Books in the Liz Carlyle series in order

For MI5 Intelligence Officer Liz Carlyle the nagging complications of her private life are quickly forgotten at Monday's Counter-Terrorist meeting. An invisible may have entered mainland Britain. An 'invisible' is a terrorist who is an ethnic native of the target country, who can cross its borders unchecked. Who or what is the target?

When Intelligence Officer Liz Carlyle learns from one of her agents that suspicious meetings are taking place at an Islamic bookshop, she trusts her instinct that a terrorist cell is at work. Her boss, Charles Wetherby, immediately puts a surveillance operation into place. An attack seems imminent.

Liz Carlyle has been transferred to Counter-Espionage, along with her research sidekick Peggy Kingsolving.