The knock on the door came at midnight on Friday. I was awake — I had been working through the coordination document for the second-stage case, which had grown considerably since Tuesday and was now forty-one pages and colour-coded in six colours, which was perhaps three colours too many but I had committed to the system. The knock was not from the street door. It was from my apartment door, which meant it was someone who had been let into the building — either a resident, or someone a resident had let in. I looked at the time. Midnight exactly. The Radio said: That is specific timing for a coincidence. "Agreed," I said. I went to the door. I looked through the peephole. Lia Cole. I had not met Lia Cole. I knew what she looked like from a photograph Marcus had sent — twenty-six, th

