Four Navy officers walked in, three of them in identical toga suits whose ebony surface effect rippled in subdued patterns. Their seniority was evidenced only in small red dots glowing on their shoulders. He recognized all of them without having to reference their u-shadows. Mykala, a third level captain and the local ftl drive bureau director; Eoin, another captain who specialized in alien activities, and Yehudi, the Arevalo office commander. Accompanying them was First Admiral Kazimir Burnelli. Troblum hadn't been expecting him. The shock of seeing the commander of the Commonwealth Navy in person made him stand up quickly. It wasn't just his position that was fascinating, the Admiral was the child of two very important figures of the Starflyer War, and famous for his age: one-thousand-two-hun-dred-and-six years old, seven or eight centuries past the time most Highers downloaded themselves into ANA.

The Admiral wore a black uniform of old-fashioned cloth, stylishly cut. It suited him perfectly, emphasizing broad shoulders and a lean torso, the classic authority figure. He was tall with an olive skin and a handsome face; Troblum recognized some of his father's characteristics, the blunt jaw and jet black hair, but his mother's finer features were there also, a nose that was almost dainty and pale friendly eyes.

'Admiral! Troblum exclaimed.

'Pleased to meet you, Kazimir Burnelli extended a hand.

It took Troblum a moment before he realized what to do, and put out his own hand to shake — suddenly very pleased his toga suit had a cooling web and he was no longer sweating. The social formality file his u-shadow had pushed into his exovision was abruptly withdrawn.

I'll be representing ANA: Governance for this presentation, Kazimir said. Troblum had guessed as much. Kazimir Burnelli was the essential human link in the chain between ANA: Governance and the ships of the Navy deterrent fleet, a position of trust and responsibility he'd held for over eight hundred years. Something in the way he carried himself was indicative of all those centuries he'd lived, an aura of weariness that anyone in his presence couldn't help be aware of.

There were so many things Troblum was desperate to ask, starting with: Have you stayed in your body so long because your father's life was so short? And possibly: Can you get me access to your grandfather? But instead he meekly said, 'Thank you for coming, Admiral. Another privacy shield came on around the chamber, and the net confirmed they were grade-one secure.

'So what have you got for us? the Admiral asked.

'A theory on the Dyson Pair generators, Troblum said. He activated the chamber's web node so the others could share the data and projections in his files, and began to explain.

The Dyson Pair were stars three lightyears apart that were confined within giant force fields. The barriers had been established in AD 1200 by the Anomine for good reason. The Prime aliens who had already spread from their homeworld around Alpha to Beta were pathologically hostile to all biological life except their own. The Starflyer was one of them that had escaped imprisonment, and it had manipulated the Commonwealth into opening the force field around Dyson Alpha, resulting in a war which had killed in excess of fifty million humans. Eventually, the force field had been reactivated by Ozzie and Mark Vernon, ending the War, but it had been a shockingly close call. The Navy had kept an unbroken watch on the stars ever since.

Centuries later, when the Raiel invited the Commonwealth to join the Void observation project at Centurion Station, human scientists had been startled by the similarity of the planet-sized defence systems deployed throughout the Wall stars and the generators that produced the Dyson Pair force fields.

Until now, Troblum said, everyone assumed the Anomine had a technology base equal to the Raiel. He disputed that. His analysis of the Dyson Pair generators showed they were almost identical in concept to the Centurion Station DF machines.

'Which proves the point, surely? Yehudi said.

'Quite the opposite, Troblum replied smoothly.

The Anomine homeworld had been visited several times by the Navy exploration division. As a species they had divided two millennia ago; with the most technologically advanced group elevating to post-physical sentience, while the remainder retroe-volved to a simple pastoral culture. Although they had developed wormholes and sent exploration ships ranging across the galaxy, they had only ever settled a dozen or so nearby star systems, none of which had massive astroengineering facilities. The remaining pastoral societies had no knowledge of the Dyson Pair generators, and the post-physicals had long since withdrawn from contact with their distant cousins. An extensive search of the sector by successive Navy ships had failed to locate the assembly structure for the Dyson Pair generators. Until now, human astro-archaeologists had assumed the abandoned machinery had decayed away into the vacuum, or was simply lost.

Given the colossal scale involved, Troblum said, neither was truly believable. First off, however sophisticated they were, it would have taken the Anomine at least a century to build such a generator starting from scratch, let alone two of them — look how long it was taking Highers to construct Air, and that was with near unlimited EMAs. Secondly, the generators were needed quickly. The Prime aliens of Dyson Alpha were already building slower than light starships, which was why the Anomine sealed them in. If there had been a century gap while the Anomine beavered away at construction, the Primes would have expanded out to every star within a fifty lightyear radius before the generators were finished.

'The obvious conclusion, Troblum said, 'is that the Anomine simply appropriated existing Raiel systems from the Wall. All they would need for that would be a scaled-up wormhole generator to transport them to the Dyson Pair, and we know they already possessed the basic technology. 'What I would like is for the Navy to start a detailed search of interstellar space around the Dyson Pair. The Anomine wormhole drive or drives could conceivably still be there. Especially if it was a "one shot" device. He gave the Admiral an expectant look.

Kazimir Burnelli paused as the last of Troblum's files closed. 'The Primes built the largest wormhole ever known in order to invade the Commonwealth across five hundred lightyears, he said.

'It was called Hell's Gateway, Troblum said automatically.

'You do know your history. Good. Then you should also know it was only a couple of kilometres in diameter. Hardly enough to transport the barrier generators.

'Yes, but I'm talking about a completely new manifestation of wormhole drive technology. A wormhole that doesn't need a correspondingly large generator: you simply project the exotic matter effect to the size required.

'I've never heard of anything like that.

'It can be achieved easily within our understanding of worm-hole theory, Admiral.

'Easily? Kazimir Burnelli turned to Mykala. 'Captain?

'I suppose it may be possible, Mykala said. 'I'd need to reexamine exotic matter theory before I could say one way or another.

'I'm already working on a method, Troblum blurted.

'Any success? Mykala queried.

Troblum suspected she was being derisive, but lacked the skill to interpret her tone. 'I'm progressing, yes. There's certainly no theoretical block to diameter. It's all down to the amount of energy available.

'To ship a Dyson barrier generator halfway across the galaxy you'd need a nova, Mykala said.

Now Troblum was sure she was mocking him. 'It needs nothing like that much energy, he said. 'In any case, if they built the generators on or near their home star they would still have needed a transport system, wouldn't they? If they built them in situ, which is very doubtful, where is the construction site? We'd have found something that big by now. Those generators were moved from wherever the Raiel had originally installed them.