They stand in the middle of a expanse of red dirt, land stretching out and out into the distance. She stands across from him and his Tardis but he gives in regardless mid run and turns, collapsing to his knees as she just watches.

"What do you want Missy?" He cries out, chest heaving with exertion. Dust clings to his clothes and he knows he probably looks like crap. Somehow she has avoided all of this and is still perfectly put together, not a hair out of place or a particle of dirt to be found. She stares at him blankly, chest so still he almost doubts she is breathing. Something about her unsettles him more than usually. There is something beyond wrong with her.

She raises the gun.

"I am not Missy." She says. Her flat voice carries out endlessly.

"Then the Mistress- the Master, whatever name you go by now-" He calls out in irritation. She does not respond. They fall silent.

The Doctor picks himself up, uncaring of the dust covering his trousers.

"Who are you then?" He asks warily, "Where is my friend?" The silence chokes them now, suddenly stifling. She says nothing still, face not even flickering for the Doctor granting her her dearest wish.

"I am the Murderer." The Time Lady replies simply.

The Doctor's face falls even further.

"No! No, you can't do this." He shouts. Her expression remains unchanged.

"Missy!" The Doctor cries.

"I am not Missy." She reaffirms. The tone changes only slightly but the Doctor catches the wavering.

"What did they do to you?" He asks, horrified, rushing forwards. Tenderly he cups her face in his hands. She continues to look at him calmly, not reacting except to place the gun against his left heart. He studies her face.

"Koschei?" The Time Lord questions softly.

She collapses. She feels him rifle through her mind and he lets out a curse.

"Never you." She says, gasping out the words, "Even with them inside my head." Her face twists as if she ate something incredibly bitter. Her lips tremble, skin a pained white.

"Never you." She spits out, shaking now.

"Never ever you." She insists, dropping the gun from her shivering fist. He holds her up against himself as her legs begin to give way.

"No. Missy!" He keeps panicking, "Not again! Don't leave me again! Please- you can't, Mistress!" A tear comes from her eye as she stares up at him, eyes blown wide.

"I'm scared. I'm scared Doctor." She sobs.

They drop to the floor together, the Doctor cradling her head against him, lips sticking as he cries over her.

"You're going to be okay. You can regenerate. Please Mistress." He strokes her hair as he speaks, rocking gently. Her lips part, red sickly against her pale face. She looks so young he thinks in that moment.

"No. I can't. Then I'll lose." She swallows, "My control. Without it they'll get you."

"No." He says again, "No!" He holds her close.

"You look so beautiful," She says, eyes drifting.

"So beautiful." Her face smooths over, vacancy overtaking her mind as he desperately grips tight, trying to pull the information from her. He has to- there's a cure- there has to be.

It goes.

"Like a star, Doctor." She says, lips falling slack.

"Beautiful." He takes her up in his arms, still sobbing.

"Koschei."

There's one tear left on the brink of her eyelid.

It leans forwards and inches down her face before dropping into the dust and disappearing forever.