"But he-" Miriam stared. "Where does Mom come into this?"

"I had orders to get those records to you." Olga looked unhappy. "And your mother took them."

Miriam rolled her eyes. "She was in the same town at the same time, right?"

"Yes." The set of Olga's shoulders relaxed. "On its own that would not be conclusive, but-"

"You're telling me my mother, who spends half her time in a wheelchair these days, assassinated a doctor, stole several thousand sets of medical records, and made a clean getaway? And why? To stop me from getting my hands on the breeding program's records?" Her emphasis on the last three words made Olga wince.

"I am uncertain as to her motive. But-your mother knew of the program, no? And you must needs be aware of her views on the balance of powers within our circle of families, yes?"

Miriam sighed. "Of course I know what she thinks of-of all that stuff. But that breeding program was just plain odious. I know why they did it, I mean-we're dangerously short on world-walkers, and if we can use a fertility clinic as a cover to spread the recessive trait around, then pay some of the first generation women to act as donors-but I tend to agree with Mom that it's destabilizing as hell. And ethically more than questionable, too. But why would she destroy the records or kill Darling? Was there something else we don't know about?"

"I don't know." Olga looked troubled.

"Then why don't you ask her?" Miriam crossed her arms.

"Because." Olga bit her lip. "She killed Dr. Darling," she said, conversationally. "She had her woman Mhara do it, in direct contravention of Security protocols. The other thing, Helge, that you did not let me get to, is that there was another witness present."

"Really?" Miriam's shoulders tensed.

"Dr. yen Hjalmar," said Olga.

"I want him dead." Miriam's voice was flat.

Olga shook her head. "We need to find out why she killed Dr. Darling first. Don't we?"

"But-" Miriam changed tack. "Brill thought ven Hjalmar was dead," she said. "In fact, she told me so."

"Hmm. There was some confusion after the palace- Perhaps she was not in the loop?" Olga leaned back and met Miriam's eyes. "I am telling you this because Mhara's first loyalty is to Security; she was most upset when she learned her actions were unauthorized. What is your mother doing, Helge? How many games is she playing?"

"I… don't…" Miriam fell silent. "Dr. ven Hjalmar," she said faintly. "Is she cooperating with him?"

Olga stared at her for a long time.

Summer in the suburbs. The smell of honeysuckle and the creaking of cicadas hung heavy in the backyard of the small house on a residential street in Ann Arbor; there was little traffic outside, the neighbors either already in bed or away from their homes, dining out or working late. But inside the house, behind lowered blinds, the lights were on and the occupants were working. Not that a casual interloper would have recognized their activities as such…

Huw sat in front of a laptop in the day room at the back of the house, staring at the running Mathematica workbook through goggles as it stepped through variations on a set. Wearing an oxygen mask, with a blood pressure cuff on his upper arm and a Glock on his belt, he squinted intently as the program flashed up a series of topological deformations off a familiar knot.

On his left wrist, he wore an electronic engineer's grounding strap, which he had attached to a grounding spike in the backyard by a length of wire-and tested carefully. Two camcorders on tripods monitored his expression and the screen of the laptop. The medical telemetry gear was on order, but hadn't arrived yet; it would have to wait for the next run. There were other watchers, too, equipped as best as he'd been able to manage in the time available.

"Ouch." Huw tapped the space bar on the keyboard, pausing the run. "Sequence number 144. I definitely felt something there." He glanced round. "Elena? You awake back there?"

"This thing stinks." Her voice buzzed slightly. "And I give you seven more minutes until changeover time, my lord. Would you mind hurrying up and getting it over with?"

Huw stretched, rotating his shoulder blades. "Okay," he agreed. "Resuming with sequence number 145 in three, two, one"-he tapped the space bar again-"ouch! Ow, shit!"-and again. Then he reached down and hit the start button on the blood pressure monitor. "That was a definite… something. Ow, my head."

The machine buzzed as the cuff inflated. Thirty seconds passed, then it began to tick and hiss, venting compressed air. Finally it deflated with a sigh. "Shit. One fifty-two over ninety-five. Right, that's it for this run. I got a definite ouch."

Huw closed the workbook, then removed his goggles and unclipped the oxygen mask. "Ow." He rubbed at his cheeks and the bridge of his nose, where the rubber had chafed. "How are you coping?"

"Help me out of this thing?" Elena asked plaintively.

Huw stood up, detached the grounding strap, and stretched again. "Okay, let's see.." Elena was fumbling with the gas regulator under her visor. "No, let me sort that out." A moment later he had the visor unclipped and her helmet swinging open.

"That's better!" She took a deep breath and began to unfasten her gloves as he attacked the straps holding her backpack in place. "Are you sure the real thing will be lighter?"

"No," Huw admitted. "And that's if we can get our hands on one in the first place. I think we're going to end up having one custom made." Pressurized suits with self-contained air circulation weren't widely sold, and some of the suppliers he'd approached had responded with alarming questions; the line between civilian and certain military uses was rather thin, it seemed. "Here, you should be able to get your helmet off now."

"Oh, that's nice." Elena began to work at the high-altitude suit's catches. It had been a random find in a somewhat peculiar store, and had taken almost a week to restore to working order; so far it was the only one they had, which had put a serious cramp on experimentation until Huw had bitten the bullet and decided to work with an oxygen bottle and goggles as minimal safety precautions. "How do you feel?"

"Head's splitting," Huw admitted. "Hmm. Let me just check again." He ran the blood pressure monitor again. It was roughly the same-alarmingly high for a fit twenty-something-but he was standing up and moving, rather than slouched over a computer: Good. "I think I'm coming down."

"It was definitely a tingle? Stronger than the last?"

"I think," Huw paused for thought, "I'm going to skip forward a couple of notches, see how far this sequence runs. I got two weak ones, then this"-he winced-"like tuning in an old radio."

"A radio? A radio tuned to new worlds?"

"Maybe." He detached the blood pressure cuff and walked over to the archway leading to the kitchen. "I'm more interested in knowing what class of knot we're dealing with."

"What kind of?… But it's a knot! How many kinds are there?"

"I don't know." Huw glanced at the coffee machine, then the wine bottle sitting next to it. "Huh. Where's-" The door chime pinged for attention.

"I'll get it." Elena was out of the boots and gloves; she'd managed to unzip the pressure suit as far as the crotch, revealing the rumpled tee shirt and jeans she was wearing inside it. Huw shook his head. "That'd better not be the Jehovah's Witnesses; they're going to think we've got a really weird family life."

"You say that like it's a bad thing-oh hello there!" Her voice rose to a happy chirp as Huw looked round. "Come in, be you welcome! He's in the kitchen, over there, Huw-"

Making a snap decision, Huw palmed the corkscrew and picked up the bottle. Turning, he paused in the doorway. "Sigfrid? What are you doing here?"