Basically, after spending a month going through every single magic book in William's study, Dawn had come to one conclusion.
She had to suck it up.
And open the damn rift.
It wasn't a good thing to do — no, wait, scratch that. It was a terrible thing to do! One of the most irresponsible, stupid, insane things Dawn could ever even think of doing!
"But he's making her sleep with him," Dawn muttered. Collapsing over the book. "Every second I delay… he's making her…!"
Oh, God, did Dawn wish she still had access to some serious firepower.
"I am so going to kill you when I find you, Billy," Dawn muttered, plucking up the book she needed from the shelf. Opening it to the page she wanted. A magical spell. To open the rift. Collect the right ingredients and… she'd be good to go. "And you better hope, when Seo gets free, that I find you, first."
She tucked the book under her arm, and went out to go ingredient hunting.
"Because between me and Seo," she muttered, locking the door behind her, "I'm the nice one."
Seo sat in 'the Spot', her head bent, curled up into herself. Unwilling to move. Unwilling to do anything. Unwilling to even acknowledge the man before her.
"You've been like that for days."
Seo didn't respond to him. Didn't answer.
"I hate seeing you miserable."
Still, no answer.
William came over, closer to her. "I can make you stand up," he pointed out. "I can make you speak to me. Make you sing for me. I can even make you feel happy."
Seo looked up. Her eyes dark. Biting.
"You've already imprisoned me forever," she snapped. "Isn't that enough?"
William didn't answer.
"I want," Seo said, "to go home. Visit Mom and Jack."
"Why not?" Seo demanded. "What threat could they be to you? What threat could any of my friends be to you? I'm not going to risk killing everyone just to escape."
"Oh, I doubt you'll be able to escape," William said. "But you still can't visit your friends from the future. Because the future won't be there for very much longer."
Seo jumped to her feet, advancing on him, eyes blazing. "What?!"
"It appears your Aunt Dawn," said William, "doesn't want to leave well enough alone after all. She's about to open the rift. In 1826."
Seo felt a sense of dread well up in her hearts.
"Of course, opening the rift won't release you," said William. "But it will release Abaddon. He will wander the Earth, draining the life from everyone on this planet. All will die. And the future will cease to be."
"Oh, you thick, thick man," Seo said.
William didn't seem terribly concerned. Or upset. "It won't matter — you exist outside of time," he said. "You'll remain, even if the future gets destroyed." He shrugged. "I don't delight in destroying humanity's future. But if it's between humanity, and losing you… I'm not giving you up."
Seo felt herself shaking — with fury, fear, horror, she wasn't exactly sure. "Billy," she said. "Listen to me. Very carefully. If you want this universe to survive, you have to let me go."
"No," said William.
"Don't you get it?" Seo shouted. "If Dawn opens the rift, it won't just be the future that will end! It will be everything! Absolutely everything!"
William scoffed. "I've seen the rift open," he said. "It doesn't—"
"I'm the Key," Seo interrupted.
William stopped. Frowned. "You're… the… what?"
Seo stepped forward, her eyes dark, as she grabbed him by the shoulders. Shook him. "Listen to me. You didn't imprison a Time Lady. That's the disguise my creators used to hide what I really am, inside. I'm a trans-temporal, trans-dimensional, trans-universal Key that can unlock and destabilize any portal I'm in. You've trapped me at the intersection point between the rift and the real world. Which means the moment Dawn opens that rift, everything everywhere will collapse."
It was a lie. But not much of a lie. Everything everywhere would collapse if Dawn opened the rift — that part was true. But only because it was Dawn, specifically, opening the rift, while Seo, specifically, was the one stuck inside it. The combination of their two energies, without Seo's mind in full control?
Biggest boom in history.
"Do you understand, William?" Seo demanded. "You have to let me go to 1826. Talk to Dawn. Convince her not to do this. Or everything is going to end. Everything everywhere."
William thought this over. Then laughed. "I don't think so."
"I'm not as stupid as you take me for," William said. "You're not getting in touch with your aunt to save the world. You're just trying to be clever. Trying to escape. You have a plan."
Seo, in desperation, spread open her arms. "Read my mind!" she said. "Go on! I don't care how!" Actually, she knew how he'd do it. Either he honestly didn't know how to read people's minds without having telepathic sex with them, or he just liked rubbing it in her face. Either way, the moment he entered her head, that was what he was going to be doing. "Just read my mind and see that I'm telling you the truth!"
His eyes went dark. Intense. As he looked at her with an animalistic desire.
Seo shuddered. Her arms lowering, as she backed away.
Realizing… when she wasn't bewitched… when he wasn't manipulating her… she couldn't do this. Just couldn't. Couldn't stand the thought of him in her mind, invading, reaching his grubby little fingers into the essence of everything that was her. Couldn't stand the idea of him wrenching open the center of her psychic essence and stealing her for himself, again. Taking her over… as his puppet… once more…
"On second thought," Seo said, turning on her heels, "never mind!"
She ran. Raced forward, fast as she could, struggling against the gnawing lethargy still clinging to her from his psychic influence. Her mind reached out for the energies of the rift. She could see them, now, clearer than ever before — her chains, what he'd done to her, how he'd bound her to the edges of the rift.
She grabbed hold of the chains, balancing herself between inter-dimensional energies, and used them to launch herself deep into the rift's heart.
"Seo, don't you dare—!" she heard William shout.
But she never heard him finish. As she entered the rift.
If she was lucky, she might not end the world. If she was lucky — extremely, insanely lucky — she'd manage to pull off her plan in a way that allowed her to avoid the world-ending catastrophe she was about to begin, just by escaping from this prison in the first place.
There was a 95% chance that, if she did this, she'd destroy the world.
But… compared to Dawn opening the rift… end of the world wasn't looking so bad.
"Oi! Easy there, Harkness!" Alison said, grabbing a large alien gun out of the Torchwood van and checking it over. "Moment I finish university, my soul belongs to Torchwood. But until then… it's all mine." She waggled a finger at him. "So hands off my soul."
Buffy, nearby, tried to stifle a laugh.
"Jack?" came Gwen's voice, through the headset. "The aliens — they've scattered."
"All right — Yan, go east, Gwen, go west," said Jack. "Rest of us are on our way." He turned to Alison and Buffy. "Sounds like it's time to split up."
"First I sell you my soul," said Alison, charging up the gun, "and then you split up with me." She gave Jack a grin. "You know, I'm sensing some relationship issues at Torchwood already." Then turned and raced off into the distance.
Jack and Buffy looked after her.
"You've been training her, huh?" said Jack.
"Yeah, well, you didn't, and it got her stuck in the 1970's," Buffy replied. "So I took over." A look of pride spread across her face, as she watched Alison skillfully pursue and then round up the aliens, nearby. "She's good, isn't she?"
"Good at the fighting," Jack said. "And good at the banter. My kinda gal."
Buffy sighed. "Just don't lose her again," she said, as she pushed past him, and off to pursue the aliens in the opposite direction. "Because next time, I really am going to kill you, Jack Harkness. Several times. Don't forget that."
Ianto skittered to a stop. Stared at the apparition before him.
It was an apparition, this time.
Faint, like something trying to break through into this reality, but… just… not able to do so. But the ghost's features were all clear enough for Ianto to recognize. The face exactly what he remembered.
"Ianto, listen, I don't have much time," Seo's ghost said. "And I know this is going to sound mad, but you have to open the Cardiff Rift."
"You must be joking," said Ianto.
"No, really!" said Seo. "Find Tosh, get her to input settings 568-Z-alpha-4, and tweak the calibrator five clicks to the left…" She tilted her head. "Or was it… the right…? No, wait, left. Definitely left."
Ianto felt his mouth go dry. Tosh…
"Tosh will know what to do!" Seo insisted. "Just find her, tell her I'm stuck in…"
Seo stopped. Looked around herself.
"Uh oh," she said. Waved at Ianto, calling out, "Got to go!"
Then vanishing completely.
For a moment, Ianto couldn't even speak.
Then a furry, fuzzy, yapping alien thing raced by Ianto's feet, and Ianto rushed after it, full pelt, once more.
Gwen jumped. Spun around, to find Seo standing there, just behind her, looking insubstantial — translucent and ghost-like.
"Gwen, listen," said Seo. "I don't have much time, so just let me talk fast."
Gwen crossed her arms. Giving the apparition a hard, cold stare.
"I'm trapped in the Cardiff Rift," said the ghostly form of Seo. "And you have to use the rift manipulator to open it to get me out. I told Ianto how to do it, but didn't tell him the risks. Truth is, there's going to be about a 95% chance that, when you open the rift, you'll end the world. But that's all right — because if you don't open the rift, there's a 100% chance that you'll end everything else. Any questions?"
"Yeah," said Gwen. "Why'd you think I'd actually fall for this, again?"
"It's true!" Seo's ghost insisted. "Gwen, look at me! I shouldn't be able to get through to you at all. He's locked me out of this entire time-zone. But the walls of reality… right around here and now… they're too thin. Far too thin. Something's about to happen, Gwen — and it's going to destroy everything. Everywhere!"
"Nope," said Gwen. "Not buying it."
The ghostly form of Seo cursed beneath her breath. Then froze. Looked around herself, her eyes terrified. "Got to go!" she shouted, as she faded out of sight.
Jack spun around. And immediately pointed his gun at the ghostlike image of Seo, standing just in front of him.
Seo's ghost put her hands in the air.
"Jack, listen to me," the ghost-Seo said. "Please. I'm stuck in the Cardiff Rift, and—"
"Nice try, Bilis Manger," said Jack. "But she's been asking me to open the rift since she got here."
Seo froze. Her mouth dropping open. "Bilis…"
For a few seconds, she said nothing. Sudden realization spreading through her.
"I knew," she breathed. Stumbled back, a little. "Right at the beginning! The moment he mentioned Abaddon, I knew… Billy… Bilis…" She shuddered. "That was the moment I worked it all out. The moment I knew exactly what was going to happen to me. And what it meant." She looked deep into Jack's eyes. "And I couldn't stop it. It had already happened, in my past. So I locked everything about Bilis Manger out of my memory… so he wouldn't see it when he invaded my mind." She put a hand up to her head. "And now… it's all happening. Just the way Bilis said it would."
Jack still didn't seem impressed.
"Change of plans," said Seo's ghost, dropping her hands. "Don't open the rift. Don't touch the rift manipulator. If Billy's going to turn into Bilis, then I need another plan. I need to…" Seo paused. Her eyes going wide, as something struck her. "Oh, God, Jack — he's going to kill it," Seo muttered. "Bilis wouldn't hesitate. That means the moment William gets desperate, works out it's something under the ground, and not on top of it — he'll find my Spot. Make the flickering stop. Dig it up, so he can destroy the brightness, forever."
Jack lowered the gun. "Your… Spot…"
"There's something… no, someone," said Seo, her teeth gritted. "Buried beneath Cardiff. Been buried for about 2,000 years, now. I don't know who, or why, and Billy's screwing with too many of my senses to figure it out, but… whoever is buried there… they freed me, Jack. They made me remember who I really was. Remember you. And I need you to dig them out, before Billy destroys them."
Jack stared at her. A sudden chill coming across him. "Seo," he whispered. "How… why are you in 1820? Buffy said… you were looking for someone…"
Seo instinctively reached up a hand, to pat down her bangs. "Not important."
"Who?" asked Jack.
"Just someone from the 51st century out to kill his brother," said Seo. "He hooked up with a Time Agent and ran away when I put him on time out for killing a bunch of people. But I'll deal with him, later. After I save the universe."
She looked over her shoulder. Grimaced.
"Got to go," she said. "Mom and Alison have to be in 1826. I remember that. I just have to work out some way to get them here."
Then she raced off, and faded out of existence.
Buffy turned a corner, to discover…
"Seo?" Buffy asked. She tiptoed around the apparition, not sure if this was real or just some weird psychic whatever thingy.
"Mom," said the ghostly form of Seo. "I need you and Alison in 1826. Right now. Dawn's about to open the rift and I need you to stop her."
"Dawn's… what?!" Buffy shouted.
"It's not her fault!" insisted Seo. "I got trapped in the rift, and she's trying to rescue me. But the end's coming, Mom. I can feel it, around this time zone. Whenever I punch through. It's like… everything's falling apart."
"Maybe it's some… paradox, from Billy interfering with my past," said Seo. "Or reality leaning towards a probability in which the universe has already ended. I don't know. But I need you in the past. And to do that, I'm going to find some way to manipulate Cardiff history so that you and Alison can get here and stop Aunt Dawn."
"Seo, what—?" Buffy started.
"No time!" said Seo. "Just… remember. If you never see me again. I… love you. And…" She gave Buffy a long, sad stare. "Tell Jack I love him, too."
As she faded out of existence.