From the former head of MI5 and author of the bestselling At Risk comes a heart-stopping new thriller that returns us to the high stakes world of MI5 Intelligence Officer Liz Carlyle. When Liz 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, Director of Counter Terrorism, trusts her as well and immediately puts a surveillance operation into place. An attack seems imminent. So Liz is surprised when Wetherby suddenly takes her off the case. And she's shocked to hear the reason why: he has received a tip-off that a mole is at work inside British Intelligence. If true, then the potential damage to the Service itself could be immeasurable. Now, as her colleagues scramble to avert a terrorist strike, Liz must find out who the mole is, and what their intentions are, before it is too late.