Setting a trap for a person who travels in both time and space is quite simple. Create the appropriate bait, any time, any place: eventually the prey will sense that bait and be captured.

The Daleks knew what bait would be most appropriate for the prey they sought. They had studied time travel and time war, in several variations: artron torque, reflectile projection, timescoops. For this particular bait, they were constructing a time corridor.

The corridor stretched through the Vortex, an invisible finger of fire spanning both the years and the light-years. One end of the time corridor was anchored on a small green world, rich in life. The other end was not fixed; it wavered across nearly half a degree of galactic arc. But the averaged calculation of its location would have placed it very close to a certain planet in the constellation of Kasterborous.

Both of these planets were of interest to the Doctor. And therefore, of interest to the Daleks.

After the corridor was built, the Daleks scattered in their great ships like shy spiders. They observed their surroundings, they attacked those who attacked them, and they experimented with revelling in several dimensions. They met alien races, mapped far star systems. They refined themselves. And they waited. Waited for when and where a certain entity would enter their web of a single strand, and the shuddering of his passage would resonate, drawing them to him.

# # #

"I can't free the TARDIS from the time corridor!" shouted the Doctor, clawing at the control panels as they and the entire control room unexpectedly tipped from the horizontal. The TARDIS was shaking like a jellyfish in a whirlpool.

"Isn't there anything you can do?" pleaded Tegan, as she tried to retrieve Turlough from the wall where he had been hurtled by the time craft's shaking. His normally pale face was even paler, and she wasn't feeling very well herself.

"No, too much turbulence. We can't materialise, we're risking breakup." The Doctor shook his hair out of his eyes and moved another control, then two in sync, but the ship kept tumbling.

The Cloister Bell gave its deep chortling ring, signalling the TARDIS' peril. Tegan tensed, clinging to the control panel tight enough to whiten her fingers.

"What are you waiting for?" Turlough demanded, his eyes flickering over the TARDIS' displays. "We can't take much more of this."

The Doctor adjusted another control. "The time stress varies, I'm waiting for the right moment to break free. And - here it is. Hang on!"

He hit several controls in quick succession, and the Cloister Bell seemed to ring in all three of them; the ship and its occupants shivered, every bolt and panel and nerve and cell starting to grind and lurch to break free of the rest.

# # #

The Bell was not heard only in the TARDIS. Across time and space, on hundreds or even thousands of Dalek ships, the warning was heard. The intercept forces prepared themselves, charging their weapons, downloading the latest and most refined battle plans. Signals were sent and received.

And not only Daleks heard and responded. Certain vital non-Dalek personnel were notified, woken, recalled, or released from the stasis fields that had held them frozen in time, waiting for this one most precious day.

Kaled scientists started their program routines and brought their equipment online. Tremendous mechanical constructs in great irregular shapes like reefs of grinding steel were powered and primed, aligned and focussed.

Kaled troops grinned, teeth bright against space-tanned faces or pale ones, as they took up their weapons. Others ran fingers over weapons controls, double-checked defensive systems, prepared their minds and bodies. Some pulled out tokens of the Horned God from under their clothes, cupping them in their hands as though to keep them warm, and kissed them, asking for His strength. They mustered for the battle of their lives. Literally.

# # #

The TARDIS seemed not to stop, but rather to congeal. Tegan could free one hand from its death grip on the console, to rub at her churning stomach. "Are we loose?" she asked weakly.

"Yes. Now we need to find out where that time corridor is heading."

"Can't we just leave it?" Turlough asked, fidgeting with his school tie.

"What? Nonsense, it would be like leaving an electrified cable stretched across a dark room. At knee height," he added, as he scanned the TARDIS' displays. "We'll have to move parallel to the time corridor, find its endpoints," and then he just stared, his blue eyes seeming to cloud over.

"Doctor. Doctor, what's wrong?" Tegan had seen despair on the Doctor's face before, but not like this.

"Oh. Well, the time corridor has two ends. One of them appears to be anchored on Earth. Late twentieth century, to be exact."

"And the other end?"

"Ah. Well. The other end is not anchored, currently. But."

"But?"

"It's pointed straight at Gallifrey," he said faintly.

# # #

While the Doctor and his companions debated the meaning of the time corridor, a signal was pinging against the TARDIS; a signal that only she could hear.

The signal was not unexpected. The TARDIS knew what it meant. To the last possible iota of meaning, she knew what it meant. And she was sorry, so terribly sorry, as she replied.

# # #

"It's a trick," said Tegan hotly.

"It's a trap," said Turlough. "The Time Lords want you back on Gallifrey; they want to force you to be President. So they're threatening Earth…"

"No, Turlough, no. That's not their way."

"What, they don't threaten people?" Tegan's mouth was set in a hard line; she had recently been on Gallifrey, in the Death Zone, and she had found it quite intimidating - not that she would ever let it show.

"To threaten Earth - no, they would surely see that as interference."

"Then it's a trick," said Tegan again. "Who else could they be hoping to capture?"

The Doctor turned away from both of them, nervously running one hand through his flyaway blond hair. He stared blindly at the white wall of the TARDIS, and did not notice something very important happen. It was Turlough who saw that the time rotor had stopped.

"We've materialised," he said, moving back to the TARDIS controls.

"What?" said the Doctor, looking for himself. "You're right. We're dead in space. And-"

He touched another control, and the screen in front of him lit with a simplified display: a plain rectangle for the TARDIS, surrounded by many overlapping oval shapes.

"And what?" asked Tegan, staring at the mysterious screen.

The Doctor gave a slightly nervous grin. "And we're not alone." The TARDIS viewscreen opened, and all three of them looked up to see nothing.

Literally nothing; solid blackness.

"Where are the stars?" asked Tegan. "I thought you said we were in space."

"We are," replied Turlough. "But there are multiple objects around us."

"What sort of objects?"

A single point of light suddenly winked on the screen, and then was joined by a second. A string of lights, reminding Tegan of nothing so much as tiny lanterns in a ship's rigging. The lights formed an arc that became a giant circle.

And then another circle appeared.

And another.

Spaceships. Great saucer-shaped ships, clustered so thickly around the TARDIS that they blocked out the stars. They were motionless in relation to the box captured in the centre of their formation. They seemed to huddle together, close enough almost to touch, as though they were cold and the TARDIS was a tiny blue flame that could warm them.

Tegan shivered; for an instant she thought the Bell was striking again. It was impossible to judge exactly how big those ships were, but she had the unpleasant certainty that they were very, very big.

"I'm not recognising their design," said the Doctor, eyes dancing between four sets of outputs. "But there are a lot of concentrated energy sources inside them."

"Like - batteries?" Tegan asked.

"Like weapons," the Doctor said, his blue eyes grim.

"Doctor," said Turlough hesitantly.

"Not now, I need to find out their flight path, their planet of origin - if I can," said the Doctor, flipping more controls.

"Is that what you're asking them?"

"What?" the Doctor said, his eyebrows suddenly knit.

"Well, we're transmitting," said Turlough, pointing to a tiny readout in front of him, and a single flashing light.

The Doctor moved quickly, almost shoving Turlough aside. He stared at the light as he flicked two controls, three, five, held down two buttons and then shouted, "NO! Stop!"

"What's happening?" The control room suddenly plunged into darkness, then lit again before Tegan could catch her breath.

"The TARDIS is transmitting to those ships - its own personal transponder signal. And they're responding. I've got to stop it!" The Doctor flicked more controls, and then dove under the control panel, pulling his sonic screwdriver out of his tan coat's pocket and holding it, not like a tool, but like a weapon. He rolled onto his back and started loosening panels.

"Is there anything we can do?"

"Yes, Turlough. Try and break the signal, turn off the transmitter, divert the power, scramble it, encode it, anything!"

Turlough's white hands flicked at the TARDIS' controls again and again, but he was out of his depth, and whatever he did the TARDIS seemed to route around. He had always been fascinated by the Doctor's marvellous travel machine, moving at will in time and space. He sometimes thought of it - of her, as though she were alive, just as the Doctor appeared to. But now she seemed to be mocking him, teasing him, deliberately subverting and twisting and ignoring his every effort. Data streamed away under his fingertips, and he was helpless to stop it.

"Doctor, they're leaving!" said Tegan with joy in her voice. On the screen the saucers were drifting back, forming themselves into great squares or cubes. Those cubes were moving away, looking like a game of improbably regulated ring toss, and she could see the real stars now between them.

"I'm afraid they may have gotten what they wanted," said the Doctor, standing and then clenching his screwdriver in his fist for a moment. "The TARDIS transponder signal and identification codes."

"So - what?" Tegan asked. "Are they gonna run up bills on your charge card?"

The Doctor looked exasperated. "They didn't just get the transponder signal, Tegan. They captured everything they could get on Gallifrey's defences: the transduction barrier, the Citadel blueprints, everything. And with the transponder-"

"What's so special about the transponder signal?"

Turlough's voice was faintly supercilious - or maybe not so faintly. "I presume the Doctor is saying that they could pretend to be a TARDIS."

"Not just any TARDIS, Turlough. The President's TARDIS, the ship the High Council and Flavia are expecting back at any moment. They could send that signal, and Gallifrey would drop her defences. I must warn them."

The Doctor dematerialised the TARDIS, and with the rasp of the engines came another sensation: that of being pulled backwards through endless invisible layers of icy-cold wet velvet, sticking and smothering and tearing with their passage. The frozen rippling pressure squeezed against all of them, hard enough to bring tears to their eyes.

The TARDIS crew shouted, but only the Doctor's shout had any sense.

"Vortex magnetron!" he shouted. "It's got the TARDIS!"

Tegan crossed her bare arms over her chest, clenching her fists. Whatever was happening, it was not good.

# # #

The time rotor stopped, and they all seemed to hold their breath for a moment. Even the TARDIS was strangely silent.

"Where are we?" Turlough finally asked.

"We are - three days after we met the saucers in space. And we are on Gallifrey." The Doctor shook his head from side to side. "A vortex magnetron, set to drag us here and now - but why?"

"Maybe we shouldn't try and find out," Tegan offered, still feeling shivery and strange.

"No. We have to find that magnetron and deactivate it, or we'll just be hauled back to Gallifrey. And we have to warn the Council!" The Doctor touched the door controls and dashed through them, heedless of his companions' protests as they followed.

None of them noticed the tiny silver bead that rolled out of the TARDIS doors after them. It slid between two stone tiles and was gone.

"And this is?" Tegan asked doubtfully, looking around.

"I'd say this is the - the Citadel Second Ring Gardens," the Doctor replied, scanning the neat array of square pots, arranged in little groups of four and bearing plants with square leaves and neatly angled stems, all framed by a square room without windows. It was like a garden, except surrounded by cold stone and steel walls and lit by cold overhead lights. "It always seemed a bit overgroomed to me."

"Why are all the plants covered with wires?" Turlough asked as they picked through them, heading for the large doors. While the plants' leaves might be green or yellow or deep red, they were alike in being wrapped and caged in strands of silver wire.

"Those? Oh yes. The gardener has to maintain an elaborate mathematic model of how each plant is supposed to grow, you see. And if the plants don't match the model, well. It's not Gallifreyan, to change the model. So he, or she, binds the plants." The Doctor reached out and touched one particularly rambunctious-looking purple vine; it seemed to strain against the thick cable twisted around it, forcing it into a cube. "Always felt rather sorry for them, actually. Back in the day."

They had gotten to the doors now, great towering things three times the height of a man, and the Doctor pulled them open. "I just hope Commander Maxil isn't waiting for us," he said with a joking note in his voice.

"Who's Commander Maxil?" Tegan asked, following through the doors.

"Oh, a very stuffy member of the Citadel Guard, much too fond of his own helmet and breastplate and shooting people."

"Does he have curly blond hair?" Turlough asked from behind them.

The Doctor and Tegan stopped. "Yes," the Doctor said.

"Well, perhaps this is him."

They turned and saw Turlough leaning over in a particularly stiff way, as though trying to keep from touching the fallen figure that lay behind the door.

The Doctor and Tegan came back, and saw a man smothered and covered with a thick white blanket of what looked like paste. Its irregular edges adhered to the floor around him, and there was a translucent bubble of the stuff over his face, shivering a bit with his breath - at least, Tegan hoped it was his breath.

His round face was a bit slack, and his eyes were closed. He might have been asleep. His hair was matted to his forehead in sweat-stiff curls, and the edge of something metal showed under his chin.

"Maxil," the Doctor said softly, going on one knee. "Maxil, can you hear me? Maxil!"

Maxil just lay there. The Doctor leaned forward, sniffing.

"Whatever this stuff is, it smells - augh!" he shouted, shoving himself to his feet and then flailing to keep from going over onto his back. The blanket had reared as he leaned close, sending tendrils towards his face. He stepped even further backwards, and the stuff subsided, melting back into the layer over Maxil.

"Tegan. Turlough. What does that smell like to you?"

"I don't smell anything," said Turlough, and Tegan agreed. The air was flat and sterile, with maybe a faint hint of mushrooms.

The Doctor leaned forward, stretching his neck and keeping his hands at his sides, and breathed out with an audible whoosh. At the touch of his breath, the white thing boiled again.

"Interesting," the Doctor said, leaning back prudently. "Some sort of organic substance, highly reactive. It appears to be triggered by chemicals carried in the breath. Gallifreyan breath, to be specific. And it smells quite - intoxicating, actually. I wonder." He looked at Maxil, pinned and wrapped on the floor like a Christmas present that couldn't be trusted to remain under the tree. "This may be some sort of life support system, recycling his water."

"Recycling his-" and Tegan noted how the stuff coiled like threads into the corners of Maxil's mouth. Presumably those same threads could be all over him. Soaking up his sweat and - everything else; filtering it for re-use.

"But what is it for?" The Doctor frowned, pursing his lips.

"Emergency survival equipment?" Tegan could imagine bundling up airplane passengers in this stuff before a crash - or maybe even before, in some cases.

"Yes, but what's the emergency?"

At least part of the emergency was revealed as they went on: destroyed doors, long parallel scrapes on the immaculate gleaming stone floors. And people, lying here and there as though dropped, and all of them covered with the white organic sheets. Time Lords in elaborate heavy robes and rigid flaring collars; guards in red and white uniforms that barely showed through the rippling layers over them.

The Doctor stopped at the intersection of two corridors. "Now that way," he pointed, "is to the Council Chambers, and that way is to the Panopticon. So - which way?"

"Doctor, there's something down there," said Turlough, standing alert and tense. In the direction of the Panopticon there was a rushing noise, and a buzzing.

"Perhaps we should try the Panopticon first," said the Doctor, striding confidently in that direction. There was something about that buzzing sound that made the hairs stand up on the back of his neck, but he didn't let it show. He strolled as though without a care in the world.

As they moved through the corridors, Tegan tried to decide what was familiar. The only other building she'd even seen on Gallifrey was the Tomb of Rassilon, and that had been a fortress. This was a fortress in disguise, she decided: stone with Art Deco slabs of gilded metal laid over it, and pretty lights and tamed flowers and little dancing fountains here and there. But the stone showed underneath, like a skull.