Slowly, the Doctor sat up, her gaze fixing on each of the people in the Matrix Chamber in turn. "Who are they? Are we having a party? Oh...all those memories. The Matrix...the memories blew the Matrix." The Doctor grinned. "Oh, she's clever. I'm clever. We're all clever. All of us. However many that is." She stood and turned, immediately seeing the way the Doctor and Master were knelt, holding Ash's body. For a second, the Singer was terrified that the Doctor wouldn't care. After all, she had just discovered the entirety of her identity. The Singer would always think of her as the Singer's sibling, but there was no way to know the Doctor would feel the same about her. "What happened?"

But she did care, because the concern in the Doctor's voice broke through all the facades she attempted to put up around the companions.

"Was going to ask you the same thing," the Master snarled. The Doctor moved forward as if to come towards them, but the Master aimed a weapon at her chest, forcing her to stop.

"Whatever you did to the Matrix," the Singer's voice was shaking, "I think Ash accidentally took it too." She turned back to her son and brushed a bit of Ash's hair off his face. "Charity must have known what happened. She's going to come with them."

The Doctor frowned. "With who? What did Charity do?"

"Took after her father," the Master said. "Made an army of Cybermen using Time Lord corpses to save the universe."

The Doctor stepped forward, waving a hand at her companions for them to move behind her. "I can't let that happen." She didn't expand on it, just stared at the Singer and the Master, willing them to understand.

"She has the Cyberium inside of her," the Singer said.

"Do you want to stop her?" The Doctor was entirely speaking to the Singer then.

"I want to save her."

The Doctor looked to the Master. "I know that you don't want them to turn into you. If the history between us means anything to you..."

"The history between us is the rage and pain in my hearts," the Master's voice was quiet. The Singer remembered what the Doctor had told her of the Master's secret fears for the Singer. She could almost hear them discussing the same about the twins.

The Doctor nodded. "We will stop and save her."

"How?"

The Doctor gave them a small smile and turned to the humans, registering them fresh again. "You shouldn't be here. No humans on Gallifrey."

"If it helps, we have explosives." One of the humans said.

"And a plan," Ryan added.

"A Cybership's parked up in the middle of your hometown," Graham said. "It's ripe for blowing up."

"We're going to strategically place bombs around the ship, including some close enough to the core."

The Doctor pointed at the humans. "Yes. Good. Do that. But it won't achieve everything. We're fighting a race of Cybermen led by a young woman who can see the future. We need to be discrete. Distract her. Can't let them off the planet. Have to be stopped. And your bombs aren't going to do that. We need more!" She spun again, looking back at the Singer and the Master. "But there isn't anything more. She would have thought of everything..." But then her eyes widened. "That's what's been bugging me. That's the thing that he said to me."

"What thing who said?"

"The half-converted Cyberman."

The Singer nodded. "He's still alive. Following Charity like a puppy."

The Doctor snapped at her. "'The death of everything is within me.' That's what he said. Oh, what did it mean?"

"There's a myth around him," one of the humans offered. "The Death Particle. The legend is, he, it, whatever, has a particle in a tiny chamber inside its chest. It will take out all organic life on a planet."

"That's grim," Ryan said.

"Or it's a solution."

"If Charity hasn't removed the Death Particle from him."

The Doctor frowned. "Is it possible to remove it without activating it?" The humans who knew the mythology shrugged in answer. "Let's assume it's still there and work from there. We need a timer on an explosive to activate the particle. Clear evacuation plan."

"Only if you've got a way to get us off this planet before it hits."

The Doctor looked to the Singer, her question asked silently, even without a mental bond.

The Singer frowned and focused on her bond with TARDISes. Since landing here, she'd only heard her own TARDIS song. She hadn't even bothered to look for the rest – given that she now remembered that they had been among the first the Master had targeted. But now, if she looked...there were two. He'd left two.

The Singer nodded.

"Right," the Doctor said. "You all good to set those explosives?" the humans nodded. "We'll deal with the rest. Meet in the corridor below the carrier. Go on, then." She gestured the humans to the door. The humans just managed to make their way around where the Singer and Master still were. It was only when they were alone again that the Doctor spoke. "You bring Ash to that TARDIS and send me where it is. I'll attempt to get the Cyberium out of Charity."

"You're not going alone," the Singer told her. "Do you even have a plan yet?"

The Doctor ground her teeth. "I'm working on it."

"Work harder," the Master snapped.

"You are going to help us carry Ash, and then we are going to Charity together." The Singer gestured for the Doctor to join her and the Master around Ash. "Come on."

Thankfully, the Doctor didn't object to that. Together, the three of them carried Ash while the Singer led the way to the TARDISes.

"I didn't expect you would have left any TARDIS alive," the Singer said to the Master as they walked.

"Too sentimental for my own good." The Master's voice was tight and the Singer knew without looking that he and the Doctor exchanged a look at that statement, a degree of understanding passing between them.

The doors of the bland shell of the TARDIS opened as they neared. The song was eager and friendly. Gently, the three of them laid Ash down. Before leaving, the Singer adjusted his hair and the Master kissed his forehead. The Doctor only watched.

When the other two went to the door, the Singer ducked back down and took his weapon. Yes, she was going to save her daughter, but there were still Cybermen involved.

"I told him to keep his glasses on at all times, no matter what," the Master was saying to the Doctor once she returned to the other two. "Of course he never listened."

"He's our son," the Singer raised her eyebrows, "of course he didn't."

The Doctor paused, as though she was listening. "They're running."

"The humans? You can hear them?"

"Gallifrey is quiet." The Doctor turned to them. "We need to meet them and bring them to the TARDISes."

As she finished, they heard the clear sounds of the Cyber-carrier exploding above them.

"If Charity was still on that ship..." the Master said.

"She can see the future, can't she?" The Doctor waved a hand. "She'll be fine."

"Please be a bit more concerned about my daughter," the Singer said. "Your niece."

"Yes, isn't she." The sharpness in the Doctor's voice made the Singer and Master pause, slowly turning on their heels to face her. "What?"

"I never asked what you thought of your history." The Singer had heard the concern in the Doctor's voice earlier over Ash's fate, but perhaps that had just been guilt. The Doctor was terribly empathetic, even if it wasn't to the specific level of Ash. "Your identity."

The Doctor ran her tongue across her teeth. Glanced at the Master and the Singer wondered what the pair had said to each other for those few minutes after the Singer had left them in the Matrix. "You think you've broken me? You'll have to try harder than that." She almost smiled. "You've given me a gift. Of myself. You think that could destroy me? You think that makes me lesser? It makes me more. I contain multitudes more than I ever thought or knew. You want me to be scared of it because you're scared of everything. But I am so much more than you."

The Singer blinked, something sinking in the pit of her stomach. "Fine then. Go save your little humans." She turned and strode off, her anger burning through her. She tried to center it, tried to focus it on the task of finding Charity. Of saving Charity.

Tried not to think about the fact that the Doctor, her sister...had denied her. Had moved away. Had claimed the technical truth that this revelation about her true identity made her so much more than the Singer or the Master. So much more than the twins.

It hurt more than the Singer would ever be able to say.

"You don't even know your own life," the Master told the Doctor, staying behind for a few seconds longer than the Singer. His cruelty now was in response to the Doctor's, for taking the stand she did. "Look how low I have brought you. I have won, Doctor. You may have made us, but I have destroyed you." He caught up with the Singer quickly, taking her hand for a few seconds. "We don't need her."

The Singer squeezed his hand. "Can you track Charity?"

"Harder without a mental bond. But I do believe that I can find her." He held up a finger. "Hear that?" Distantly, they could still hear the approach of Cybermen...and Charity singing pure nonsense.

"Did you completely neglect to teach them subtlety?"

The Master shrugged. "Why bother with that?"

It did not take long to find Charity. She was walking at the head of her army of Cyberman, stretching back far into the corridor. The half-converted Cyberman was just a step behind her. At this point, Charity seemed to be glowing silver from the Cyberium.

"Ah, mummy, dadaidh." Charity stopped walking far too sharply to be natural. All of her Cybermen followed suit. "Blowing up my Cyber-carrier wasn't very nice."

"Terribly sorry about that, my dear," the Master said. "The Doctor's idea. You know how she gets."

Charity snorted. "So much potential, and she just squandered it in a charity shop."

"I'm surprised how calm you are, given Ash's current situation."

Charity frowned. "And what is that?"

"Unconscious."

Charity actually sparked at that, electricity rippling through all of her veins. She stumbled forward, though not far enough that the Singer or Master had to catch her. "What...happened?" her voice was clearly forced out, like she had to constantly actively fight something inside of her.

The Singer had a horrifying guess that it was the Cyberium.

"He wasn't wearing his glasses. Got overwhelmed. He's safe. Waiting for you." The Master took a careful step forward, his eyes still trained on his daughter. There was a simple truth to his words, but the Singer recognized his care there.

Particularly now, with all her memories from those days back on Gallifrey and newly re-regenerated, the Singer was thankful that the Master had been the one to raise the twins. He was fierce and harsh and cruel, but he was still their father. He still, above all and most importantly, loved them.

"I should have been..." Charity sparked again. The Master just kept walking closer. "We had a plan, an agreement. He knew the risks he was taking..." Another spark. "We needed the army."

"And you made one wonderfully." The Master was barely two steps away from Charity now. "I'm very proud of you, Charity, my beautiful sweet. You've done wonderful."

Charity's eyes looked wet, though that may have been the silver glow of her skin. "We're going to finish what you started."

"I told you, you need to blaze your own path through the universe." The Master took the second to last step. "Turn your own heads. No need to finish what I started, or copy me. Or rely on Cyberium."

As the Master and Charity stared at each other, some silent battle of wills as he tried to force the Cyberium out of her, the Singer felt someone step up next to her.

She didn't turn. Didn't hope.

'The history between us,' the Doctor said, 'means everything to me, little sister.' Her voice was impossibly light across their mental bond.

A/N: The Doctor's back! Time for a final showdown!

Notes on reviews:

Guest: Yes, the Singer is selfish and arrogant, particularly as she's grown up. She's always been very protective of her own, even above all others.