Graham's friend brought them to a rooftop, where they managed to stun the creature from the train.

"Get in!" Ryan cheered. "It actually worked!"

The twins both took out their vaporizers. They kept the devices down so that the Doctor and the humans couldn't see them, but the twins wanted to be ready.

The Doctor frowned at him. "Of course it worked. I'm not an amateur." She circled the creature. "Overloaded its socket, stunned it for a bit. Not sure for how long though. Best be quick." She glanced at Graham. "And thank you to Kevin the bus driver for location intel."

"See? Always ask a bus driver."

The Doctor crouched before the creature, taking out her newly built sonic to scan it. "Half organic, half machine. Starts to make sense now. Wait..." she frowned. "It's a Gathering Coil...no, dozens of Gathering Coils. These tentacle-y things, they're creatures which gather information. They've been lashed together and augmented into one super-creature. But why? What data are they gathering? Unless..."

"So that's an alien species?" Yasmin asked.

Ash had to fight himself from answering instead of the Doctor. Charity was the one who knew the future and had to stop herself from spoiling things, but Ash knew the present now, and it pulled at him.

"Not really," the Doctor cut in, pulling his attention away from himself. "More of a semi-species. Weaponized bio-tech."

Charity glanced behind them, knowing there would be someone there, though she told only Ash.

"You said there were two aliens in a battle."

The Doctor nodded. "You're right, I did, but now I think I'm wrong and I'm trying to catch up with what that might mean. If I can access the data it's gathered..." she stuck her screwdriver into the coils and activated an image, projecting it into the air. It was a human that took the twins a moment to recognize, even as they had made a habit of remembering faces.

"It's Karl from the train," Graham said.

"Karl's the data. That's what it was gathering on the train."

"But what would the alien want with him?"

"Which one of you shall I kill first?" They all turned to see the alien from before. On instinct, the twins stepped forward, drawing their weapons.

"I'm voting none of us," the Doctor said. Ash knew the Doctor didn't see the weapons. Didn't even really see the twins right now, no matter how hard they'd tried to reveal themselves to her again. "Get behind me now." The twins didn't move. "You two, now." The twins, to appease her, took a step back. The alien didn't move, as though it recognized the weapons the twins held. "Stop right there. Come any further and we'll blast whatever that thing is."

"You're interfering in things you don't understand."

The Doctor shrugged. "Yeah, well, we all need a hobby."

"You're not human." The alien looked between the twins and the Doctor. "Who are you?"

"Me?" the Doctor pointed at herself as if she hadn't noticed the alien including the twins. "I'm..." she snapped. "Oh, it's gone again. I had it a minute ago. So annoying. Same question back at you." She held up a hand. "No, in fact, before that, because it's really bugging me, actually not bugging me, offending me. Why the teeth? Bad enough you kill, why take a tooth from the victim?"

The alien removed its faceplate, revealing a face studded with teeth. "A Stenza warrior wears his conquests. You may tell your children you were once privileged to encounter Tzim-Sha of the Stenza."

"Tim Shaw?"

"Tzim-Sha."

"Tim Shaw," the Doctor nodded.

"Tzim-Sha! Soon to be leader of the Stenza warrior race, conquerors of the Nine Systems."

'I remember them,' Ash told Charity. 'Cold skin.'

The Doctor tilted her head. "When you say soon to be leader, what are you now, the office junior?"

"Eh? No, don't wind him up."

"Tonight is my challenge. Trace and obtain the selected human trophy."

Her eyes widened. "It's a hunt. You're on a hunt."

"Well done. Your tiny mind must be burning with such effort."

"Did he just say I had a small mind?"

Charity bit her tongue.

"The challenge is simple. Our leaders randomly designate a selected human. I'm sent here, alone, no weapons, no assistance. I must locate and obtain the trophy and return home with it, victorious. By doing this, I ascend to leader. This is the ritual of the Stenza."

Yasmin gasped. "And it's happened before. Rahul's sister."

"Earth is not a hunting ground."

"Access was granted."

Ryan shook his head, pointing at him. "No, it wasn't. It was a misunderstanding. Access revoked as of now, by me."

Ash raised his hand, drawing everyone's attention. "You said the rules were no weapons, no assistance."

The Doctor pointed at him. "Good point."

Tzim-Sha nodded. "Correct."

"So you killed the humans with your cold skin, but you're not meant to have the Gathering Coil, are you?" He could explain later how he knew about the cold skin, if the Doctor even remembered it as odd at all. At this point, the twins were very much doubting it would peak her newly regenerated notice.

"The creature is irrelevant."

The Doctor shook her head. "I don't think it is. I think you smuggled it ahead of you. I think it located the randomly designated human for you. I think you broke the rules. Some leader you're going to make. Tim Shaw is a big blue cheat!" Tzim-Sha raised his hand, his palm glowing with something blue. If he took another step, the twins would shoot. The Doctor just raised her hands. "Okay, fine, have it."

The group stepped back from the gathering coils while the twins stepped to the side, allowing Tzim-Sha to crouch by the creature and touch it. The energy seemed to flow into him.

"What's it doing?" Ryan asked.

"Total transference," the Doctor said. Tzim-Sha stepped back from the creature. "If you've finished, let's be really clear. You're not taking any human from Earth tonight. Leave now or we're going to stop you."

"Good luck." There was a bright flash of light, nearly blinding, and when it faded, Tzim-Sha was gone, and the creature with him.

"No!" The Doctor turned in a small circle, grabbing at the air in irritation. "Short-range teleport. Double cheat!"

"Where have they gone?"

Charity looked back to the Doctor. "To hunt."

"Hunt who?"

The Doctor raised her eyebrows. "Isn't it obvious?"

-I-I-

They shoved themselves into the car again, trying to find any indication of where Karl could be, given they knew he'd left them to go to work. Yasmin attempted to call him, but it was Ryan who found Karl and his workplace online. Charity had flashes, but they both weren't helpful and would have very heavily indicated to everyone involved that the twins were not who they said they were before the Doctor spoke of it themselves.

Graham guided them to the building site. The Doctor leaped out of the car once they arrived, though the twins followed her as quickly as possible. They ran through a hole in the fence and found a dead body, his radio still broadcasting.

"Dennis, I need help!" Karl called through the radio. "Somebody's on my crane!"

The Doctor groaned. "Oh, great. Karl's a crane operator. He would be, wouldn't he?"

Ryan pointed up. "It's over there."

"And that creature's guarding the bottom of it." The gathering coils circled the base of the only turned on crane.

The Doctor turned to the humans. "Graham, Grace, Yaz, I need you to take this equipment and get everybody off this site. Don't care how. Use your initiative. Do not come back in, understand?" The two humans nodded, and the Doctor looked to the twins and Ryan. "Ryan...what are your names?"

"Ash and Charity Saxon."

The Doctor flinched at the names but didn't seem to recognize she'd just done that. As if the twins had entirely escaped her memory. "Good. Ryan, Ash, Charity, how are you with machinery, and heights?"

The twins grinned.

-I-I-

The four of them ran to the crane next to Karl's. "That tentacle-y thing is guarding Karl's crane, so we go up this one."

"And what are we doing once we're up there?" Ash asked.

"Don't worry, I've got a plan."

"Really?"

"Well, I will have by the time we get to the top." The Doctor turned and started to climb. Charity followed immediately, but Ash paused, looking back at Ryan.

"Are you alright? You can just guard the bottom." Even with his glasses on and intentionally not looking Ryan in the eyes, Ash could not fight his sense of the man's worry.

Ryan clenched his jaw. "I can do this." Ash nodded and let Ryan start to climb before following.

The Doctor got about halfway up before she gestured for Karl's attention. "Oi! Karl from the train. Up and over! Up and over!" the human thankfully seemed to hear her, as he climbed out of his cab.

Ash had been focusing on that when Ryan's foot slipped, making him drop his torch. Ash just managed to lean back and catch it. "You okay?" Ryan nodded and they kept climbing.

Finally, the group reached the top, looking towards Karl's crane, where he was slowly making his way towards them. "We made it!" Ryan cheered. "Oh!" he glanced below them. "Oh, no, no, no, no, no...it's way too high up here."

"Your plan?" Charity prompted.

"Nearly...nearly, nearly..." The Doctor snapped her fingers. "I got one. I climb onto the arm of this crane, you swing the arm round next to Karl's crane."

Ryan's eyes widened. "Oh no, you're kidding."

"Karl steps across, you swing the arm away, I get him back in here, all back down for a cuppa and a fried egg sandwich. I'm really craving a fried egg sandwich. Simple, no?"

"And the cranes will line up?" Charity asked, knowing they wouldn't.

"All right, it's a work in progress, but so is life. I'll be fine. Oh!" she pulled a handful of keys from her pockets. "I got these downstairs. One must work." She shoved them into Charity's hands. "You can figure out how to work a crane, right? Go." Without waiting for a nod, the Doctor ran out to the arm of the crane.

Ryan swallowed hard. "Okay, I can look up a video or something."

The twins turned to face the cab in unison. "No need."

"How do you know how to work a crane then?"

"Don't quite know it yet." Charity focused. Specifically knowing the future was tricker than what she tended to do, which was passively let an understanding of where they needed to go or do come over her. Sometimes, she could find a thread and follow it all the way to the end, seeing quite far into the future with specificity. Thankfully, this time she didn't need the distant future, she just needed the future of a few minutes from now, when she was fully capable of driving a crane.

The twins knew some technology, but they'd never had the chance to actually drive a crane.

This was going to be fun.

A/N: The twins are still hiding from the Doctor, but that can't last forever ;)

Notes on reviews (spoilers for 1/1/20 episode):

Purplestan: The Doctor will definitely have more of a chance to get to know the twins since they're older...and pretty much stuck together. Definitely did not expect that cliffhanger from the New Years episode! I have so many ideas both about how the Master and what each of those ideas could mean for the Singer. Can't decide which is my favorite, so now I'm just hoping they'll tell us sooner rather than later! And happy birthday! :)

Guest: Don't worry, you were successfully vague. Had no idea what was happening until the moment it did!