Carey searches for one suspect, whilst Frank Napier deals with another. As the evidence mounts, and Carey is forced to avert another catastrophe, she begins to fear she might have made a terrible mistake. Not that Napier cares. He's using his own unique brand of interrogation to test Carey's theory.
Pierson's first day on the job gets ever more challenging, but as the net tightens for James Whitlock, it looks like SO15 might have made a breakthrough in the case.
