His boots. He took each one off and felt around inside them, then by chance and out of desperation, turned them over. It was there, on the right boot, tucked in the angle between heel and arch. The glue hadn’t adhered properly to the dirty underside, and half the tab was flapping around, folded back on itself. The plastic cover had worn through, and some of the circuitry had been severed.

Where had he gone? Walked the short distance up past the palace to Green Park. Straight from Chain’s office to Oshicora’s. It had to have malfunctioned before then, otherwise he’d have been overheard organizing a half-million-euro counter-hit with Oshicora. That Chain had missed that was down to pure, unadulterated luck.

Petrovitch was at the end of the line. It was time to get off and change trains, right now.

14

On Monday morning, everything had been fine. By Tuesday lunchtime, he was teetering on the brink of disaster, and might even be over the edge of the abyss.

The thought he struggled with was that he’d walked right into Oshicora’s private park and met with the man himself without getting the once-over for weapons or wires. Or maybe he had, and the security was so discreet that he hadn’t noticed. Perhaps the inside of each and every lift was a screen.

Sorenson hadn’t been pushed against a wall and shot—not yet. It was a good but confusing omen, adding another element of doubt to a critical choice: whether to ditch his current identity and sleeve up with a new one. He’d done it once before, to get out of St. Petersburg in one piece. He’d prepared for this moment for years. He always told himself that he’d do it if it looked like someone was close to discovering who he really was. It should have been as automatic as a reflex.

Petrovitch was twelve months away from becoming Dr. Petrovitch. Petrovitch had just written down a way to combine two fundamental forces of nature. Petrovitch was about to get a free ride to glory on the coattails of a future Nobel Prize winner. None of that would matter one iota if Petrovitch got locked up for twenty years.

The drumming of his fingers on the desk was the only outward sign that he was in an agony of indecision. He’d always assumed that it’d be his past catching up with him. Instead, he’d collided catastrophically with the future. Every time he returned to the question of whether any of this was worth imprisonment or worse, he looked down at his morning’s calculations.

There was no point in prevaricating. He knew if he stayed, Chain would get him, and if not Chain, Oshicora, and if not Oshicora, someone else. It was time to say goodbye to Samuil Petrovitch.