Author's Note: Damn, I love this story.

Every chapter just makes you wanna laugh and cry at the same time. Seo's interactions with the Doctor are just... so...!

Well, I'll let you read for yourself.

Enjoy.

"—of course, on an existential level," Seo explained, in answer to Vastra's first question, "perhaps we're all trying to work out why we're here. What's our purpose? What are we hoping to achieve—?"

"One word," Jenny Flint cut in. Again.

"Not fifty," Vastra added. "Not a thousand. Just one."

Vastra raised up her index finger as the number "one", to make the point.

Seo thought a moment. Then, on her own hand, counted the words as she said, "That's rubbish."

She revealed her two fingers to Vastra.

To make her point.

Jenny Flint hid her face in her hands, in utter frustration.

Vastra just gave Seo a hard, cold stare. "Truth is singular," Vastra said. "Lies are words, words, words. We ask you questions, and you give us a one-word answer. That's how it works."

"Did he tell you that?" Seo asked.

"Yes."

Seo thought a long moment. "One word," she repeated. Waggling her index finger. Then began counting out words on her fingers again, "I can lie with one…" she hit the last finger on her hand, then closed it into a fist, and started counting from one, "…word."

She waggled her first-finger counter at Madam Vastra.

"Six isn't one," Jenny Flint muttered.

"It is in base five."

Madam Vastra and Jenny Flint exchanged a look.

Both knew this was getting them nowhere.

"And I can lie with only one word," Seo replied, leaning back on the couch. She winced, a little, but covered it up well. "Go on. Ask me who I am. I'll lie."

"Who are you?" Vastra asked, guarded.

"Innocent."

Madam Vastra and Jenny Flint exchanged another look. Not sure how to take this.

"Of what?" Vastra asked.

"'Of what' — that's two words," Seo replied.

"We're asking questions," Jenny Flint put in. "We're allowed to use more than one word."

"Well, that's even more rubbish," Seo said. She stuck out her tongue. "How about I answer using only as many words as you use in your questions?"

"No."

"Or how about—?"

"Look, it's very simple," Vastra cut in. "Either you pass the one-word test, or you don't get to see the Doctor. That's—"

"Why isn't he seeing anyone?" Seo asked.

Jenny counted on her fingers. "That was five words," she said.

"Yeah, but it's a question, and you said questions don't count." Seo leaned forwards a little bit. "So? Why isn't he seeing anybody? Why the rubbish test and the gatekeeper and the twenty questions?"

"The Doctor lost someone," said Madam Vastra.

"Who?"

"A friend." Madam Vastra leaned against the side of her arm chair. "A close one."

Seo said nothing for a long time.

Her face draped in shadow, as she absorbed this.

The clock ticked out the seconds against the wall, behind her.

When Seo spoke again, the voice trembled, just a little. "I'm… done with this." She slowly dragged herself up off the couch. Her eyes fixed on Madam Vastra. "Done with his sulking and his wallowing and his stupid games." She strode over, her eyes blazing. Her voice very low. "He still has friends. He has you. While I…!"

She stopped.

Stood in place, in the middle of the room.

Her whole body shaking with something akin to utter desperate rage and fury and hurt, like she was about to fall apart, but didn't have the strength left to do it.

She turned away from them.

Headed towards the front door. "Just tell him I need to see him. He'll know I'm not going away."

"We're only allowed to tell him one word," Jenny Flint insisted.

Seo paused, by the doorway. Hand clutching the doorknob. "I don't need any words," she said. "I gave him an action: purposely failing his test." Wrenched the door open. "That's enough."

Then headed out of the house.

"One word," the Doctor cut in, before Vastra even had time to explain the situation to him. "What's so hard to understand about that? If they give you one word, you tell me. If they can't figure out the test — I have no interest in them."

"She flunked it on purpose," said Vastra. "She seemed to think that action would mean something to you."

"I don't care what she thought, so long as she…!" The Doctor paused. Then spun around, to face Vastra again. "Unless it's…" His face bent into thought. As if trying to weigh the possibility he might be right. "This person. Blond, short, rambles incessantly, offers everyone chocolate, acts a bit like me but nowhere near as clever?"

Vastra nodded.

The Doctor gave a small laugh, beneath his breath. "Figures. She's never been one for tests."

"You know her?" Vastra confirmed. "This… 'Seo'."

"Oh, yes," the Doctor said. "Very much so." He turned back to the central console. "Just wish you hadn't told me she was here," he muttered. "I'm not supposed to get involved with the world. And she'll—" He froze. Then spun around. "Where is she, now?"

"I don't know," Vastra replied. "She said she wasn't playing your games anymore, and left."

The Doctor pushed past Vastra. "Which, knowing her," he said, walking to the doors of the TARDIS and throwing them open, "means she followed… you…"

He stopped. Frowned, as he discovered no one lurking beyond the TARDIS doors.

"I wasn't followed," said Vastra.

"No, you weren't," the Doctor said, softly. Looking out into the distance. "But that's not like…" He hesitated in the doorway. Then grabbed up his coat, and shrugged it on over his shoulders. "Well, then. Better track her down myself and make sure she leaves. She can be extremely stubborn when she decides she's right."

Vastra hurried after him. "But… who is she?"

"Considering that my goal, at the moment, is not to interfere and not to care," the Doctor called back over his shoulder, as he descended down to the earth below, "I'd say she's my greatest antagonist!"

"Doctor, sir!" Strax announced, frog marching in the blond girl. "I have found and secured the prisoner!" He turned to her. "Welcome to this home. Obey, or you will be obliterated!"

Seo didn't seem quite so chatty, this time around. She looked tired and weary, marching in front of Strax, her every step labored and slow.

When she spotted the Doctor, she tried to hide it, standing up tall and planting an overly exuberant grin on her face.

"Hello!" Seo said.

"First off — leave," the Doctor demanded, pointing an accusing finger at her. "Second off — what are you doing here and how did you possibly manage to work out where I was? Third off — leave. And fourth off — leave."

"Without even offering me tea?" Seo said. "That's hardly fair! I came all this way — you could at least pretend you're happy to see me."

"I'm not happy to see you," the Doctor said, putting his hands on her shoulders and spinning her around. "I only came down here to make sure you left!" He shoved her towards the door. "Now! No excuses, no…"

He trailed off.

As Seo nearly fell flat on her face, barely managing to catch herself on the back of an arm chair. Her teeth gritted and face pale, as if trying desperately to hold back a scream of pain. Her hand trembled on the chair.

"You're injured," the Doctor said.

Seo planted an affronted look on her face. "No!" she insisted. She finally managed to right herself, standing on her own two feet, independent of the arm chair. But she seemed shaky. "I'm fine. Just a few scrapes and bruises. Sure they'll heal up in no time." Seo tried to step forwards, but sucked in a sharp breath. "How are you? You look more… Victorian than I remember. With the top hat and the waist coat."

"I… I'm… retired," the Doctor said. Almost mumbling the words, half-heartedly. As he noticed the discoloration around her neck and the splotchy redness in her eyes. "No more dealing with people. No more saving the world. No more getting involved."

Then realized he was really mucking up the stoic, didn't care in the slightest image, and cleared his throat, standing up straighter.

"Which means I'm staying here," the Doctor demanded, stalking towards her, finger in her face, as she stumbled back, "and you are heading right back to the twenty-first century so I can—"

Seo gave a sharp cry, as one of her backward steps slipped, twisting her leg grotesquely. She flailed around, to catch herself, but was too weak, and tumbled.

Vastra and Jenny darted out to catch her, but the moment they touched her shoulder blade, she gave a dull moan, her eyes rolled up in her head, and she passed out.

Completely unconscious.

The Doctor's eyes went wide, and he raced over to her, trying with his sonic before recalling that it gave him no readings.

"Her… leg's broken," Jenny said, examining it. She looked up at the others. "She's been walking on it the whole time, and never said a word."

"The mark of a true warrior!" Strax declared. "Never show fear in the face of your enemies! Or… your friends. Or… anybody else."

The Doctor looked up at the others. "She's not all right, at all. These should have healed, by now. And they're not close." He twisted a few settings on his sonic, activating the more dimensionally subtle settings he'd installed after meeting her, and checked again. Then tore off the sleeve of her baggy sweatshirt, to reveal…

A large patch of blistered, red-raw burned skin all covering the upper-left shoulder blade of Seo's back.

Jenny and Vastra both started, in alarm.

"She never said," Vastra breathed. She turned to the Doctor. "She seemed fine. We didn't know there was anything wrong. She made it seem like… she was…"

"Oh, Seo always lies," the Doctor muttered. "Must get it from me. Along with the astounding, unrivalled brilliance, which she also gets from me — although, in her case, it's more of a work-in-progress."

"Gets from…" Jenny repeated.

Then she and Vastra exchanged a look. As it dawned on both of them, all at once, who this was.

The Doctor gently maneuvered Seo to the ground, then bent over her, checking her pupils and measuring her pulse. Shook his head. "Too slow a response," he said. Gritted his teeth. "That silly, stupid child! Must have used up all her energy sealing off some… time breach or dimensional rift. Didn't leave herself enough strength to heal. And now she comes crying to me, begging me to interfere and solve all her problems!"

"She's… she's your… child?" Jenny said.

The Doctor looked up. "That a problem?"

"No, just… I mean, I didn't think…" Jenny tried to clear her thoughts. "Who's the mother?"

"Ah," said the Doctor. Scooping up Seo into his arms. "Long story. Complicated. Won't answer now. Or ever, come to think of it." He looked down at the drained girl. "All right, Seo. I'll get you to the TARDIS and heal you up." He turned, to address the others. "But that's it! I'm done with looking after other people, done caring, and done interfering with other people's lives. And that goes double for her!"

They all gave him the same pointed look.

"Oh, shut up," the Doctor said, leaving the house.