Memory is a palimpsest. Layer upon layer of experience, each one partially erasing the last, each one altering what came before. She had spent her career studying this. Now, sitting in the clinic waiting room, she understood for the first time what it meant.

The test was simple. Too simple, perhaps. But that had always been the point. The simplest problems, he had written in his dissertation a decade ago, are the ones that reveal the deepest truths about a system. He ran the test. The system failed in a way he had never seen before.

He ran it again. Same result. His hand was shaking slightly when he reached for the phone.

She closed the laptop. Outside, the city was still going — indifferent, enormous, relentless. She had known, on some level, that this was how it would end. Not with a bang but with a realisation so quiet it barely registered. She would need time to understand what it meant.

But first she needed sleep.