The basement beneath the Arena Hotel was more austere than the guest floors above. No red ceilings, no Nordic white wood, no polar bear skins; instead, concrete, cable trays, locked doors and LED wall lights that glowed with the utmost economy.
Claudia was still wearing her Hessian gala outfit. Dark blue, white blouse, red piping, golden lion brooch. The shoulder pads looked utterly absurd in this corridor. Claudia knew that. It didn’t bother her. You could still think in terms of nuclear physics even in very unfashionable clothes.
In front of her lay a door with no sign.
Not ‘Technical’. Not ‘Staff’. Not ‘No Entry’. Nothing at all.
Claudia took the puck out of her bag. “All right then,” she whispered. “Show me why you’re too heavy for hockey.”
Next to the door was a card reader, but not the sort you’d expect guests to use. No green light, no red light, no friendly beep. Just a narrow recess, round enough not to be a coincidence.
Claudia slid the puck inside. At first, nothing happened. Then the wall vibrated like a deep, mechanical inhalation beneath the concrete. A strip of light ran vertically down the side of the door, from cold white to pale blue. Somewhere behind the wall, several bolts unlocked one after the other.
Too many bolts for a simple cellar door; the door slid open, revealing a storage area.
It was long, high and neatly organised with wall shelves. On the left stood metal cabinets with transparent fronts. Protective suits hung inside, cream-white with grey trim, each bearing a number, size and a small seal of the Stromberg Foundation. Beneath them lay boots, gloves, sealed masks and filter units. On the right-hand side were shelves containing dosimeters, measurement tags, emergency lamps, chemical binders, sealed sample containers, spare masks and several blue boxes of iodine tablets.
Claudia stopped.
Iodine tablets at a charity gala were rarely a good sign.
She opened a cupboard door and took out one of the dosimeters. It was modern, expensive and already calibrated. No dust. No makeshift experimental setup. This area was used by people who knew that their secret must not be compromised by someone grabbing gloves in the wrong size.
She fastened the dosimeter to her lapel, just below the Hessian lion brooch.
The lion looked offended.
“Take it up with the Occupation Council,” muttered Claudia.
She took a floor-length protective coat from the cupboard and recognised the familiar weight: A highly viscous coat with lead braiding for radiation shielding, as efficient as this entire building and yet as heavy as a crushing burden. She also put on gloves, although the heavy fabric severely restricted the movement of her fingers. She took a mask with her, but did not put it on. Then she took the obligatory headscarf and hid her perm beneath the grey fabric. An emergency plan hung at the end of the room.
Claudia stepped closer.
The plan did not show what it was supposed to show. Officially, this was a maintenance wing for the arena complex’s tidal power plant: pump lines, return channels, water conduits, filter chambers. Danish channels in, Danish channels out, all nicely ecological, nicely circular, nicely harmless. Yet in the centre of the plant was a sunken ‘turbine room’ with a steam vent and a condensation tank. Tidal water had no need for either. And then came further terms in the legend: cooling water supply, secondary circuit, tertiary circuit, emergency flooding, spent fuel pool.
Claudia was familiar with everything except the tertiary circuit from back home, from the nuclear power station she herself managed in Winden. Although she was well versed in all the protocols and a supporter of nuclear energy, she shuddered at the thought that a reactor might be hidden here, right in the middle of a hotel in central Copenhagen. How could anyone have built such a thing without anyone noticing? The Danish government would never have granted permission for that. Claudia stared at the plan for a long time.
Then she understood the first lie.
The tidal power plant was not the heart of the facility. It was the narrative. The cover. And presumably a useful bonus: enough moving water, enough pumping noise, enough channels to draw cooling water from the city without anyone asking questions in the right places.
An ecological façade with an attached pipeline.
She took the puck out of the first recess again and moved on.
The next door was an airlock. This time it was labelled.
ATMOSPHERIC SEPARATION — NORTH CHAMBER
Below that were warning notices in Danish, English, French and Russian. No German. Claudia took it personally, but not for long. Next to the airlock door was another round recess.
The puck fit.
The airlock opened.
Inside, everything was too smooth. White panels, recessed nozzles, floor grilles, vertical lines of light, three cameras behind black glass. Claudia stepped inside. The door closed behind her before she could decide whether she liked it.
She didn’t like it.
An automatic scan swept over her. Blue light, then white. The air pressure changed. The air conditioning sucked at her coat, at her hood, at the big, completely unreasonable perm underneath, which bravely held its own against the blast.
A synthetic voice said something in Danish.
“Ren og godkendt”
Claudia looked at the puck in her hand.
“You and I,” she said quietly, “are clean and approved. We’ll open all the doors now.”
The second airlock door opened.
Cold air met her.
Not the ordinary cold of a technical facility. Not the dry cold of a cold store. This was a broad, physical cold, as if behind the door lay not a room, but a season.
Claudia stepped into the reactor room.
And for a single breath, she forgot to be annoyed about anything.
The room was huge.
Not high like a cathedral, but rather deep like the belly of a ship beneath concrete. Steel walkways ran along the walls. Bundles of cables hung in orderly troughs. Beneath the floor, water could be heard, but distantly, muffled by pumps and thick walls. Blue indicator lights flashed in long rows. A fine, glassy frost lay over everything, having gathered on handrails, bolts and the edges of the measuring instruments.
In the centre stood two devices.
The first was compact, almost disappointingly unspectacular: a cylindrical core in a casing of dark metal and ceramic-bright segments. Several cables led into it, several out. No steaming monstrosity, no megalomaniacal tower, no cheap theatre set for a man with too much money. Precisely for that reason, Claudia realised immediately that this was serious.
A micro-spherical cluster generator.
She stepped closer.
Through a thick viewing window in the casing, she could not see the tiny fuel spheres directly, only their shadows on the display, as if a controlled star cluster were moving within a ceramic prison. The readings on the displays were absurdly low and absurdly stable. Thermal output, conversion efficiency, residual load, cooling requirements. Everything fitted together almost too well.
“No,” said Claudia.
Not loudly. Not indignantly. Just scientifically speechless.
She leaned over a terminal. The figures told what they weren’t allowed to say: the thing was operating with an efficiency for which several ministries in Hesse would have taken turns lying to one another. Not perfect. Perfection was often just a cover for fraud. But close enough to turn every official energy presentation of the evening into a farce.
Stromberg could have bought entire countries with this generator alone.
And that was apparently not even the real scandal. Thin pipes free of ice crystals seemed to be carrying the steam to miniaturised turbines below. Claudia counted eight such pipes. Yet as much as her thoughts lingered on the functionality of this technical miniature, her curiosity drew her to the second device, to which thick high-voltage cables led from underground and which was built directly into the concrete wall, shielded by transparent walls that were not glass. Six rings floated there in a vertical arrangement, circling one another, each as large as a cartwheel, dark, heavy, surrounded by fine blue discharges. They did not rotate evenly. They oscillated. Each ring moved in a different rhythm, back and forth, tilting slightly, as if constantly seeking a position that reality refused to grant it.
Claudia felt the puck vibrate in her hand.
The Neptunium Rings.
She knew it before she read the label on the next display. 
NP RINGS 1–6 / PHASE ANCHORS
TEMPORAL OPENING: STABLE
THERMAL IMPORT: ACTIVE
Claudia stared at the words. Then she looked into the centre of the six rings. There was no hole there in the usual sense. It was more of a cut-out.
A piece of another world, cleanly and impossibly cut into the space. Behind it lay no darkness. Behind it lay white. Endless, dirty, windswept white. Snow, ice, a sky without city lights, a plain that knew nothing of Copenhagen and yet touched Copenhagen.
The air in front of the rings shimmered.
Cold poured out and vanished into a pipe in the concrete wall behind.
It ran across the floor slabs, crept up the railings, formed frost on metal and made Claudia’s breath visible in harsh, short clouds. A data set with palaeoclimatic markers ran on a side display. Not fully written out, but clear enough.
Pleistocene.
Claudia took a step back.
“You’ve tapped into the Ice Age?” she coughed into the cold.
The sentence sounded ridiculous; unfortunately, it was true.
She walked slowly around the depression. Her mind was now working faster than her fear. Six rings of neptunium as phase anchors. The generator supplied the energy. The tidal power plant camouflaged the water extraction, provided cooling circuits, and gave the pump noises an ecological excuse. The arena above was a demonstration and test site. Ice rink, high thermal load, audience, cameras, World Energy Organisation, politics. A laboratory masquerading as a festival. And if it also supplied Christiansborg Palace, Stromberg could not only lull the royal family into a false sense of security, but also cleverly divert the surplus output of this technical marvel.
Claudia hated admiration at moments like this, yet she felt it all the same. For Stromberg, who had financed such a thing even though he probably didn’t even know what neptunium was, and for the plant, which converted more energy in a tiny space than Claudia’s power station with its two reactor units.
 
The micro-spherical cluster generator alone was fabulously efficient. But the time portal solved a different problem: it didn’t generate cold. It fetched it. From a time no one took account of, from a world without owners, without permission, without waste. Cold as theft from the past.
Claudia stepped up to another terminal.
It wasn’t just technical data running there. There were project names, transport logs, error messages. One entry was marked in red.
SUBJECT DISPLACEMENT / LIND / UNCLEAR
Claudia fell very still. She read the line a second time. Then a third time.
Lind hadn’t just disappeared. He had become a reading. Behind her, something cracked in the film of ice on a railing. Claudia spun round. No one.
Only the rings, which continued to oscillate. Six dark circles, each with a tiny temporal tremor, as if they were holding open a door that should never have been built. Only now did she realise that no technical staff were monitoring these devices. The room was fully automated. Technicians were now standing upstairs, smiling at cameras, for the representative of the World Energy Organisation or the Danish princess. That was why there was no one here, but these machines didn’t need human assistants either: they did their work silently and without a guilty conscience.
She reached into her bag, took out a pen and wondered what she could jot down on.
On the back of a folded hotel card, she began to jot down numbers: ring frequencies, display intervals, warning thresholds, cooling flow, generator output. Her handwriting was quick, ugly and incorruptible. Her perms froze slightly at the edge of her forehead beneath the lead-mesh hood. She didn’t notice.
Then the puck vibrated again. A new line appeared on the terminal next to the rings.
AUTHORISATION REMAINS IN THE ROOM
SECONDARY ACCESS PENDING
Claudia looked at the puck.
“Secondary access?”
The system was waiting for someone or something.
In the airlock behind her, a distant relay clicked.
Claudia didn’t turn off the screen. That would have been conspicuous. She simply slipped the hotel card into her inside pocket, stepped back from the terminal and stood in the shadow of a control cabinet, from where she could see both devices: the compact generator, working silently and with incredible efficiency, and the impossible portal through which the Ice Age breathed into Copenhagen.
For the first time that evening, Claudia didn’t feel out of place.
She felt she was in the worst possible right place.
Behind the airlock, someone began to open a door.