Rose waits for the Doctor by the elevators.

"There you are," she says, grabbing his hand and leading him down to a side exit. "Where were you?"

"Researching and developing. Where are we going?" She's brought them outside to a parking lot.

"The control room monitors suspicious activity coming through," Rose explains. "An unidentified craft was picked up coming through our air space. Non-human tech."

"Ah." They've stopped in the middle of the lot. "What are we doing here?"

A black jeep pulls up. "Come on!" Ian calls from behind the wheel.

"Waiting for our ride," Rose tells the Doctor.

The jeep has a tracking computer built into a console in the backseat. Rose climbs in and switches it on. The Doctor gets in the front beside Ian.

"Nice vehicle," he says.

"Standard issue," Ian replies. "Alien tech spotted in the atmosphere, three miles east of here. Why do they always come to London? What's wrong with Birmingham or Cardiff?"

"Oh, I bet Cardiff's not as ordinary as you might think."

"I have the signal," Rose says. "Right where it was spotted. Control," she adds, activating her headset, "we're heading to the area now."

"Stay in contact," Control says.

"Heading out," Ian announces, and starts driving out of Torchwood.

They're on the highway, closing in on the signal, when Rose remembers something.

"Doctor, you never said. Where were you?"

"I was with my accomplice. She's going to help me find the proper materials for my...thing," the Doctor finishes lamely, glancing at Ian.

Ian is driving carefully but fast, but he spares a glance at the Doctor. "Your 'thing'? Is that an official alien term?"

"It's called a sonic screwdriver," the Doctor says shortly.

"What do you need a screwdriver for?"

"It's sonic."

"Sonic. Like sound waves? A good drill will do the same job, probably faster."

"It's a highly sophisticated, advanced piece of equipment, thank you very much."

"You just said it was a screwdriver," Ian protests.

Rose cuts in before things can get too heated. "Trust me, Ian, it's more powerful than it sounds. And who is your accomplice, anyway?" she asks.

"I met her in a development lab yesterday. She's currently working on a sonar tracking system for Torchwood, leading me to believe she has enough knowledge to know where I can find certain materials. Alien or otherwise."

"Sonar tracking?" Rose repeats. "What's that mean?"

"She didn't go into specifics," the Doctor says impatiently, "and I wasn't really interested."

"Tracking and defending bursts of alien energy and technology through sonic waves. Hopefully causing less damage to the atmosphere, since we're just recovering from global weather catastrophes."

The Doctor and Rose both stare at Ian.

"You're talking about Anna, yeah? She's my girlfriend. Been living with sonar tracking for over a year now." Ian activates his headset, leaves it on this time. "Control, we're here."


"Ready?" Rose says. Her eyes are sparkling with excitement. She's holding a tracking device that's started to beep every few seconds.

"I am," the Doctor says slowly. "Are you?"

"Well, yeah."

She's practically bouncing up and down. He hasn't seen her look so happy in a long time. His mind automatically supplies the exact length of time its been, and he shies away from the number. It's the same amount of time since he's been happy, too, and to think about how long it's really been is disheartening. He leans down without thinking and kisses her.

She blinks up at him in surprise and pleasure.

"Just like old times," he reminds her.

"Maybe better," she says, and kisses him back.

Maybe he's bouncing up and down, too, but he would never admit it.

"You two! Let's go," Ian calls.

Following the tracker, they make their way down a side street. Off of this is a small park.

"Straight ahead," Rose says. "Signal's getting stronger."

Ian leads the way, sweeping his head from left to right as he walks. "How much further?"

"A few hundred yards."

"We're all in civilian dress," the Doctor comments. "The last time I saw Torchwood everyone was in black. Have you changed uniforms?"

"We don't have uniforms," Ian says over his shoulder.

"Remember, Rose. In the Torchwood Tower when Jake and his team popped over?"

"Yeah. Sometimes we suit up in black if we're heading someplace with a lot of people. If you're going to be shooting at people or aliens, you want to be sure not to hit someone on your side."

"That is morbid."

"It may be morbid, but if you're shooting, you don't want to hurt your own team." They've come deep into the park and Ian stops to look at the tracker. "Anything?"

"A few yards ahead -" Rose stops as the beeping intensifies. "I mean, feet-"

Ian spins around, taking out his gun. The Doctor turns on the spot, scanning the area.

"I don't see anything," he says, badly wanting his sonic screwdriver. His heart is beating rapidly and in the back of his mind he thinks that he's almost gotten used to the single organ.

"Here." Rose pushes the scanner into his hands and takes out her gun.

"Rose!" He's more surprised than shocked. Where has she been hiding that?

She spares him a quick glance before moving away. "This is not our world, Doctor. The things that happen here are not the same. Torchwood is the only defense."

"I'm not criticizing, I only-"

"Will you two shut it?" Ian demands. "I'm trying to listen! How you ever managed to save the universe is beyond me."

The scanner lets out a shrill scream and stops. The Doctor looks down at the screen, then up at Rose. "Might there be an alien creature behind me?" he asks politely.

Rose nods. "Might be."

"I was afraid of that." He turns around slowly, aware that Ian and Rose have flanked him with their weapons drawn.

It is definitely an alien creature standing there. It is two meters high and has mottled green skin. Its clothing is black leather and there are two huge guns strapped to his hips.

"Were you looking for me?" it asks politely, from a face that resembles a crocodile with fewer teeth. "I believe I caught your tracking signal on my watch."

"You speak English," the Doctor says in surprise.

Rose glances at him. It took her a long time to remember that the TARDIS was no longer there to translate languages telepathically for her. For him to recall that now means its loss is still foremost in his mind. The thought hurts.

"I have a translation device."

"You've entered Earth's atmosphere," Rose says cautiously. "Unauthorized alien vehicles are prohibited."

The alien looks puzzled. "Ought I have filed a flight plan?"

"Who are you?" Ian asks. "You are an unidentified species to us."

The alien still looks puzzled. "I do not understand your question."

"I asked who you are."

"Ah, of course!" The Doctor takes a step forward. "I didn't think it was possible. Are you a Ninob, by any chance? Of the planet Nin?"

"I am."

"Amazing," the Doctor murmurs to Rose and Ian. "The Ninobs destroyed themselves during a civil war that lasted for three hundred years."

The Ninob draws itself up, making Rose and Ian train their weapons on him.

"Civil war! Ninobians have never raised arms against each other."

"Really? Huh. Interesting. This parallel universe is very unreliable," the Doctor complains over his shoulder to Rose.

"Why are you here?" Rose asks. "We represent the Torchwood Institute and we require an answer."

"My vehicle required an emergency landing. I'm having some engine trouble, you could say. I would be grateful for your assistance in getting me home."

The three of them glance around. There is no sign of a space craft, no indication that anyone in London has noticed one landing. And this London would definitely notice anything alien.

The Ninob shifts from foot to foot. "May I ask for assistance?" he asks again.

"Engine trouble," Ian says.

"Yes."

"What were you flying?" the Doctor asks. "Any sort of ship should have been visible from the sky. We monitored your ship but I don't see any sign of one landing down."

The Ninob opens and closes his mouth but says nothing.

"Pilot fish!" Rose says suddenly. "He is the pilot fish."

The Doctor starts to look around. Ian is a bit confused but follows his lead and scans the area as well.

"What is this fish you refer to?" the Ninob asks. "I am not an aquatic life form. Is my translation program missing an entry?"

"And who are you again?" the Doctor asks.

"I am ..."

"You're not here for your own purposes," Rose says. "Are you the decoy?"

"Decoy! You insult me!"

"That tears it," Ian says. He points his gun directly at the large creature. "Tell me your name. Tell me who you work for and why you are on my planet."

"He works for me," a high, piping voice says.

Everyone looks around, then up, then down.

A very short, pale creature stands behind them. If the Ninob is a ferocious-looking creature, this one looks absolutely harmless. It is wearing a dark vest and matching pants, with no weapons visible.

Ian raises his weapon, this time aiming at the small alien. Rose faces it as well, but keeps her gun trained on the Ninob.

"Who are you?" she asks.

"I am Deputy Corralin. The Ninob is in my employ."

"What is your employ?" Ian demands.

"Why are you on Earth?" Rose asks.

"We landed by mistake. We were heading to the outer part of the Malandra galaxy. Are we perhaps close to that?"

"We are unaware of the Malandra galaxy," Ian says slowly. "Care to fill us in?"

"It is my home," the alien says simply. "I believe we are lost. 'Earth', you call this place, correct?"

"That's right."

"Excellent. It should do nicely, Nonib. Notify the ship."

"The Malandra galaxy does not support life," the Doctor says sharply. "Who are you? You're not heading there. What are you after?"

The alien smiles. "We are after a home. As you said, that galaxy no longer supports life."

"What do you mean, 'no longer'? It never has."

"It has been our home for millennia. Recent changes in our atmosphere and in the worlds surrounding us have made it impossible to remain there. We are...relocating."

Rose and Ian exchange a quick glance. The darkness again, affecting worlds they knew nothing about.

"But that would make you...No way!" The Doctor's voice rises and then trails off. "You cannot settle here," he says absolutely. "You are incompatible with this population. With any population."

"Doctor, what is he?" Rose asks.

"If your world was in Malandra you must be Jennets. And Jennets were not tolerated by any other people. Am I correct?" he asks the alien.

The alien scowls. "You are correct. Our culture does not allow for inter-species mingling."

"Then you are definitely in the wrong place," Ian informs it. "This is our planet, a human planet. I am bound to inform you that you must remove yourselves at once or be taken into custody."

The alien sneers. "I hardly think so. Nonib, go."

The Nonib raises a hand that is suddenly holding a gun in it.

"Your companion is correct. We do not tolerate other species. We destroy them."

Ian reacts before the Nonib can do anything. He fires his weapon and the giant alien is thrown to the ground, covered in transparent string netting and rendered immobile.

Ian nods in satisfaction. "Nice."

He turns to the Jennet, aiming again. "That was your last chance."

"I don't think so, human." The alien pushes a patch on his vest and begins to levitate. Very slowly, but he continues to move upwards. Ian fires his weapon but it has no effect on him. He is bathed in a faint yellow glow that deflects Ian's shots.

"We have to stop him," the Doctor says to Rose. "The Jennets were so hostile to all other beings that they were encased within their system millions of years ago and eventually died out. The system has been empty ever since. If that's just now happening in this universe, they can't be allowed to escape. They'll cause death and destruction wherever they go."

"Control," Ian says sharply. "Do you copy that? Lock onto their ship. Don't let it get away."

"We have it, Ian. Backup team is approaching."

"Soon we will overrun you!" the alien shrieks. He is not even above their heads, floating so slowly it doesn't look like he's moving at all.

"You are ridiculous," the Doctor informs him. "You realize that, don't you?" He reaches up and grabs a small alien boot.

The alien growls and kicks his feet. "Release me!"

"You are not to continue on your mission. You will leave this planet and not return."

"We will destroy you and your world and cleanse it for our children!"

Rose shakes her head. "Honestly, this is an insult after everything I've just been through."

"They're locking on to your ship," the Doctor tells the Jennet. "Change your minds or it will be escorted from this planet's atmosphere without you."

"They will return for me!"

"If they do they will be shot on sight."

"Backup approaching!" a voice says in Rose and Ian's headsets. It is Riley, and she's wielding a long, slender weapon and looking very confused at the scene before her.

"This is Control. We have the ship in sight and have locked onto it with a tractor beam."

"What will it be?" the Doctor asks.

"Jennets do not negotiate with inferior races!"

Simon has come up behind Riley, holding an identical weapon. He shakes his head. "Is that an alien or a balloon?"

"We will kill you all!" the little alien vows, kicking out at the Doctor again.

"Stop that! You have to want to change," the Doctor tells him. "Otherwise the same fate will befall you again."

"Again? What again? What fate will befall us?"

"You will become extinct. You will destroy other words to the point that you will be hunted down and destroyed yourselves. That is the legacy you will leave to you children if you continue. Return to your system and resettle Malandra. I promise you the darkness is over. Your worlds should be stable and safe by the time you return to them."

"We will not," the alien grates out.

"Rose?" the Doctor calls.

"Control, lock onto the ship. Prepare to fire," Rose says.

"No! Do not. Do not."

"Return to your ship and leave our atmosphere," the Doctor tells him before releasing his ankle.

The alien glares but does not respond. He hits the patch on his vest and shoots higher up in the sky.

"Oi!" Rose yells. "Don't forget your pilot fish!"

The alien sneers at her, but a moment later the Ninob is suspended in midair.

"Control, release the ship from the tractor beam," Ian says.

"Done. Standing by for your command."

The two aliens are caught in a beam of light coming from a spaceship no one can see, and disappear.

"That was the strangest thing I've seen yet," Riley says.

"Will they be back, do you think?" Simon asks the Doctor.

"I don't know. Hope not."

"Well, that's a job well done, at any rate," Simon says briskly.

"I'll bet anything they were the disturbance we were chasing." Riley falls in step beside him.

"What the heck is a pilot fish?" Ian asks Rose.

Rose grins. "Control, job over. We're coming home."