A/N: Wow you guys! One hundred reviews in thirteen chapters?! Is that even real? You're all amazing.

Previously: "Hello, Sarah Jane."

Past and Future

Sarah Jane whirled around, a gasp leaving her mouth at the unexpected intrusion. Her eyes still showed shocked from having discovered the TARDIS. "It's you," she whispered in realization. "Wolf. Oh, my God. It's you, isn't it? Oh, you've regenerated," she realized.

The Wolf huffed out a laugh. "Yeah. Half a dozen times since we last met."

"You still look incredible," Sarah Jane told her.

"So do you," the Wolf said with a soft smile.

"Huh," Sarah Jane scoffed, "I got old. What are you doing here?"

The Wolf shrugged. "Well, UFO sightings, school gets record results. I couldn't resist. What about you?"

Sarah Jane smiled. "The same," she said, but then her face dropped. "I thought you'd died," Sarah told the Wolf, a quaver in her voice. "I waited for you and you didn't come back, and I thought you must have died."

"I lived," the Wolf corrected her sadly. "Everyone else died."

"What do you mean?"

"Everyone died, Sarah."

Sarah Jane put aside that sad topic for the moment, recognizing the Wolf's melancholy despite the new face and twenty years' absence. "I can't believe it's you," she whispered.

Suddenly, a girl's short scream ripped through the air. The Wolf immediately turned and ran back the way she'd come, Sarah Jane following close behind. "Okay, now I can!" Sarah Jane called, grinning. As they reached where the Wolf had originally split from John and Kate, the Wolf and John collided as he ran from the direction of the kitchen. John's arms flashed out to grab the Wolf before she fell. "Did you hear that? It sounded like Kate." He caught sight of Sarah Jane. "Who's she?" he asked curiously.

"John, Sarah Jane Smith. Sarah Jane, John Smythe," the Wolf introduced hurriedly.

John smiled. "Nice to meet you," he said before turning back to the Wolf. "We should make sure Kate's alright, Wolf."

The Wolf nodded. "Right." The trio took off toward the Maths department, where they quickly found Kate standing amongst a pile of vacuum packed objects.

"Sorry!" she called out as the other three arrived. "Sorry, it was only me. I was just looking through the cupboards and all of these fell on me." Kate gestured around at the packages, which they could now see were dozens of vacuum sealed rats. "I'm not usually squeamish, they just surprised me," she said, embarrassed. "I didn't mean to scream."

The Wolf grinned. "Not a big fan of rats, Kate?" she teased.

"I doubt anyone's a fan of dozens of dead rats, Wolf," John broke in, looking at the creatures with distaste.

"You can tell you're getting older, Wolf," Sarah Jane interrupted, startling Kate, who hadn't seen her yet. "Your assistants are getting younger."

"I'm not her assistant," John protested.

"Neither am I," Kate chimed in. Sarah Jane frowned as the Wolf merely fidgeted awkwardly.

"Back to the rats," John changed the subject. "Doesn't anyone else see anything strange about rats in a school."

"We never had rats," Kate agreed.

"Well, obviously they use them in Biology lessons. They dissect them," Sarah Jane said, sounding a bit superior. "Or maybe you haven't reached that bit yet. How old are you?" she asked Kate. Kate didn't answer, looking uncomfortable.

John's eyes narrowed at the strange woman's bad attitude, but he kept his cool. "No, they don't dissect rats in school anymore. Haven't done for years. They're here for something else," he told Sarah Jane calmly.

Sarah Jane looked like she was about to retort when the Wolf finally broke her silence. "Sarah Jane, you remember Kate Stewart, don't you? The Brig's daughter?" she prompted.

Sarah Jane's eyes widened and her demeanor immediately changed. "Kate Stewart?" she asked. "Katie? Oh, I haven't seen you since you could barely walk!"

Kate looked similarly shocked. "Sarah Jane, like Sarah Jane Smith? My dad told me so many stories about you," she realized.

"How is the Brig?" Sarah Jane inquired eagerly.

Kate grinned. "Trying to stay retired. Mum's being quite severe about it."

"That sounds like Doris," Sarah Jane agreed with a smile. "I haven't seen them in years," she said nostalgically.

"You used to travel with the Wolf," John finally connected the dots. Sarah Jane looked over at him, surprised.

"Everything started when Mister Finch arrived," the Wolf interrupted, wanting to avoid a fight. "We should go and check his office." Sarah Jane dropped whatever she was about to say as the three of them followed the Wolf back the way they had run.

The Wolf quickly used her sonic screwdriver on the headmaster's door when they reached Finch's office. "Maybe those rats were food," she pondered as she unlocked the door.

"Food for what?" John asked.

The Wolf quietly opened the door and peeked inside. She froze at what she saw. "Kate, you know how you used to think all the teachers slept in the school?" she murmured and opened the door a bit wider. "Well, they do." John looked up to see a number of giant bats hanging from the ceiling, their eyes closed.

"No way," Kate whispered next to him. John quickly turned her around and pushed her down the hall. The Wolf and Sarah Jane followed right behind.

"When Finch arrived, he brought with him seven new teachers, four dinner ladies, and a nurse," the Wolf mused when they had reached the relative safety of the parking lot outside. "Thirteen. Thirteen big bat people. Come on," she called, turning to go back inside.

"Come on?" John asked. "You want to go back into the building with giant bat people hanging from ceilings?"

The Wolf shrugged. "I need the TARDIS. I've got to analyze that oil you got from the kitchen."

"I might be able to help you there. I've got something to show you," Sarah Jane told the Wolf excitedly, grabbing her hand and pulling her toward a beat up looking yellow car. Sarah Jane pulled open the back, revealing a robotic looking dog.

"K9!" the Wolf exclaimed joyfully. "John Smythe, Kate Stewart, allow me to introduce K9. Well, K9 Mark Three to be precise."

Kate inspected the dog curiously. "He looks sort of disco," John pointed out.

"Oi! Listen, in the year five thousand, this was cutting edge," the Wolf defended. "What's happened to him?" she asked Sarah Jane.

Sarah Jane threw up her arms. "Oh, one day, he just – nothing."

"Did you try to get him repaired?"

"Well, it's not like getting parts for a Mini Metro," Sarah Jane said irritably. "Besides, the technology inside him could rewrite human science. I couldn't show him to anyone."

"What about UNIT?" Kate asked. "Couldn't they have helped?"

Sarah Jane's eyes narrowed. "I don't like the military," she told the teen stiffly. "I wasn't going to risk them taking K9 away from me."

"Oh, what's the nasty lady done to you, eh?" the Wolf spoke to the robotic dog in a tone John usually heard reserved for animals.

"I don't mean to hurry you along with the tin dog," John said, "but do you think maybe we could get under some kind of cover? I'm feeling exposed."

Sarah Jane drove the four to a chip shop she knew of that was close by. Once there, she and the Wolf huddled around the still inactive K9, ignoring the strange look from the waitress attending the shop. John sat at a table with Kate a few feet away. "So you've heard of this Sarah Jane?" he asked Kate.

"Oh, yeah," she answered. "Dad used to talk about her when I was a kid. She was an investigative journalist – still is, by the looks of it. Got onto the TARDIS by accident and ended up in the Middle Ages. Dad didn't know when she stopped traveling with the Wolf. One day, she just showed up at our home, told him she was back, and that she didn't want anything to do with UNIT anymore. Didn't say why. I was just a baby, but I don't think he's seen her since." Kate shrugged. "I guess it didn't end well between her and the Wolf."

John thought about what Kate said for a few minutes, watching the Wolf and Sarah Jane. They appeared to be deep in discussion. Finally, he stood up. "I'm going to get some chips for the Wolf. She's fond of them in this body. You want any?" he asked.

Kate shook her head. "No thanks."

"I thought of you on Christmas Day," Sarah Jane told the Wolf as she worked on K9. "This Christmas just gone? Great big spaceship overhead. I thought, oh yeah, I bet she's up there."

The Wolf nodded. "Right on top of it, yeah," she acknowledged.

"And John and Kate?"

"They were both there too. I didn't know about Kate at first though."

"Did I do something wrong?" Sarah Jane changed topics abruptly. "Because you never came back for me. You just left."

The Wolf sighed. "I told you," she said gently. "I was called back home and humans weren't allowed in those days."

"I waited for you. I missed you," Sarah Jane said quietly.

The Wolf dropped her hands away from K9, staring off into the distance. "You didn't need me," she said. "You were getting on with your life."

"Traveling with you was my life," Sarah Jane insisted. "The only life I knew for years. You know what the most difficult thing was? Coping with what happened next, or what didn't happen next, for that matter. You took me to the furthest reaches of the galaxy. You showed me supernovas, intergalactic battles, and then you just dropped me off on Earth. How could anything ever to compare to what we did?"

"Do you want me apologize for taking you with me? Is that what you want?" the Wolf asked harshly, voice taking on a hurt quality.

Sarah Jane shook her head. "No, I don't want you to be sorry," she backtracked. "But we get a taste of that splendor and then we have to go back," she tried to explain.

"Look at you. You're investigating," the Wolf said. "You found that school. You're doing what we always did."

"You could have come back."

The Wolf's eyes darkened. "I couldn't."

"Why not?" Sarah Jane asked. The Wolf went quiet and began working on K9 again, unable to answer the one question Sarah Jane needed the answer to. "It wasn't Croydon," Sarah finally changed the subject. "Where you dropped me off, it wasn't Croydon."

The Wolf looked over at her. "Where was it?"

"Aberdeen," Sarah Jane said drily.

"Right." The Wolf had the decency to look sheepish. "That's next to Croydon, isn't it?"

John interrupted that moment, holding a basket of chips out to the Wolf. "Sorry, ladies," he excused. "Chips, Wolf?"

The Wolf eagerly reached for the basket. "Oh, brilliant. These aren't contaminated are they?" she asked suspiciously.

John chuckled. "No, they're safe. I promise." The Wolf dug in hungrily as she continued to work on K9.

Sarah Jane stood up. "I think I'll go and catch up with Katie," she said.

The Wolf nodded. "K9 should be fixed in a few minutes. Then we can scan the oil. I'll call you when I'm done," she said absently.

Kate watched Sarah Jane walk over to her with a small bit of apprehension. The older woman wasn't much like how her father had described the plucky woman he had known years ago. She was hurt and angry, and maybe even a little jealous. "So, what's up with the dog?" she asked as Sarah Jane sat down across from her.

"The Wolf said she should have him fixed in a little bit. In the meantime, I thought we could talk," Sarah Jane said seriously.

Kate nodded warily. "What about?"

"Tell me about you. Where do you fit in this picture of the two of them?"

Kate grinned. "Oh, well, I first met them last year during the whole problem with the government at 10 Downing Street," she
explained.

"Aliens, you mean," Sarah Jane confirmed.

"Yep. I'm actually the one that blew it up," Kate said a bit proudly.

Sarah Jane's mouth dropped open. "No."

"I know, right?" Kate said excitedly. "And John called me for help last Christmas with the Sycorax. You see, the Wolf regenerated not that long ago, but she got sick from it, and he didn't really know what to do. So I came over and got sucked into the whole thing," Kate finished with a smile.

"So, you don't travel with them?" Sarah Jane asked.

Kate shook her head. "Oh, no. I started at Cambridge last fall. I actually want to join the Science Division at UNIT after I graduate, continue my father's work."

Sarah Jane nodded, reassured now that she realized her old friend's daughter was well looked after, even if she did seem to have a penchant for finding trouble. "Well, good for you, Kate Stewart. I imagine your father is very proud of you."

Kate shrugged. "Well, we don't really talk about it all that much, but I think so."

John watched the Wolf, trying to figure out how to begin saying what he wanted to without making the Wolf clam up. As he was contemplating the conundrum, the Wolf let out a cry of success as K9's head began to lift. "Oh, hey. Now we're in business."

Kate and Sarah Jane rushed over when the say K9 was working. "Mistress. Wolf," the dog said in a robotic voice.

"He recognizes me!" the Wolf exclaimed, breathless.

"Affirmative."

"John you got the oil?"

John dug in his pocket and pulled out the vial of yellow oil. "I wouldn't touch it," he warned. "It sounded like that dinner lady got scorched."

"I'm no dinner lady," the Wolf said dramatically. She cocked her head. "And I don't often say that." John hid a smile as she dipped a finger in the oil and smeared it on K9's probe.

"Oil. Ex-ex-ex-extract. Ana-ana-analyzing."

"Listen to him," Kate whispered. "Oh, I've always wanted to meet K9."

"My dog," Sarah Jane warned, but with a small smile for the teen. Kate pretended to pout.

"Confirmation of analysis. Substance is Krillitane oil," K9 spoke up.

The Wolf immediately tensed. "They're Krillitanes," she growled.

"Is that bad?" John asked hesitantly.

The Wolf nodded. "Very. Think of how bad things could possibly be, and add another suitcase full of bad," she answered grimly.

"And what are Krillitanes?" Sarah Jane asked.

"They're a composite race. Just like your culture is a mixture of traditions from all sorts of countries – people you've invaded or have been invaded by. You've got bits of Viking, bits of France, bits of whatever. The Krillitanes are the same," the Wolf explained. "An amalgam of the races they've conquered. But instead of culture, they take physical aspects. They cherry pick the best bits from the people they destroy. That's why I didn't recognize them. The last time I saw Krillitanes, they looked just like us except they had really long necks."

"What are they doing here?" John asked.

The Wolf's eyes darkened, gaining a dangerous look. "It's the children," she muttered. "They're doing something to the children."

Kate and Sarah Jane loaded K9 into the back of Sarah Jane's car while John followed the Wolf as she wandered a little ways away, hoping to speak to her privately. "How many people have you actually traveled with?" he asked.

"Does it matter?" the Wolf wondered, half to herself.

John shrugged. "Sort of. How many did you leave like Sarah Jane – wondering if you were dead, where you were?" he pushed.

The Wolf crossed her arms defensively. "I don't see the universe the way you do," she told him. "I can see when my time with someone is ending. When it's time for them to go."

"When it's time for them to go, or when it's time for you to run?" John countered, then hesitated before continuing. "Is that what you're going to do with me? Run away?"

"No, not to you," the Wolf denied instantly.

John shot her a look, startled by her answer. "What makes me so different from everyone else?" The Wolf muttered something he couldn't hear, but sounded like it could have been the word 'Everything' before she went silent, not answering him. "You were so close to Sarah Jane, once," John went on. "But now, you act like it hurts you to even think about her. Why?"

The Wolf gazed at him, looking older and sadder than he had ever seen her. For the first time, he saw all the years she had lived in her eyes. "I don't age. I regenerate. But humans decay," she said, her voice wavering. "You wither and you die. Imagine watching that happen to someone you –" she broke off suddenly, staring at the ground.

"What, Wolf?" John prodded gently.

The Wolf took a deep breath and met his eyes again. "You can spend the rest of your life with me, but I can't spend the rest of mine with you. I have to live on. Alone," she said darkly. "That's my curse for being a Time Lord," she spat. There was a pause as John just stood there, stunned, before the Wolf's eyes snapped to a rooftop as if she had heard something. John followed her gaze, both of them ducking as a giant bat swooped down over their heads before flying off.

Sarah Jane ran over, Kate close behind. "Was that a Krillitane?" she asked breathlessly.

"But it just flew off," John said, confused. "What did it do that for? It didn't accomplish anything."

The Wolf didn't say anything, eyes still fixed on the rooftop the Krillitane had come from. "We're going back to that school in the morning," she told them after a moment, still staring at the building, a determined look in her eyes.