"Seriously?" Missy asked, back to her usual sarcastically perky self. "A hobby?"

"I merely suggested that you should perhaps find something that you enjoy... Outside of arson, pillaging, murder, and all of the other things that you are on the Heriotza wanted list for", The Doctor answered, leaning on the door frame of the Vault's tall entrance. It had been a mistake, he realised that now. Well, actually he realised it the moment the words came out of his mouth. He was trying to help, he was always trying to help her, and it seemed that was his downfall. She couldn't live on synthetic dopamine. It, well, it just wouldn't be good.

"Like what?" she asked, a little offended, but also curious at the idea.

"I don't know. I'm trying to remember what you liked on Gallifrey, before, um..."

"Before I found enjoyment in arson, pillaging, murder, and all of the other things that I'm on the Heriotza wanted list for", Missy finished and put a hand on her chin. She had a good memory, a great memory even. Better than The Doctor's anyway. Poor man couldn't remember his own birthday, love him. It was the curse of the Time Lords to have good memories. It never let them forget the things they had done and the memories always hung at the back of the mind like a shadow standing behind you.
Missy never really paid any interest to anything when she was young. A quiet soul, a recluse even. While The Doctor had his head in a book, she had her head in the clouds, and now she couldn't even do that without something invading her mind.

"Think of anything?" The Doctor asked, crossing his arms as he watched his Mistress sieve through her life century by century. Missy blocked him out, taking herself further back. Back to her family home on the outskirts with its crooked windows and wooden beams from which long branches of incense plants hung, smoldering slightly. She remembered deep brown bricks and wood, curling banisters, the smell of freshly cooked meals, laughter in the air, her siblings always in a rush, her father... Let's not go there. The only thing that man loved was himself.  Missy just felt sorry for her mother. She just wanted to please him. But he never was, no matter what she did or bought or said. Missy could hear her sobbing quietly to herself at night, trying not to wake her husband. Her mother deserved more. She deserved so much more than Missy's father. His heart belonged to no one, and no one could ever take a place within it. Missy's mother, Anisha, loved all her daughters, Koschei, Strytris, Delor, Fendrath and Jodlia, equally and had such a big heart that it seemed ironic that she would give it to a man who didn't have one. Her only other love was her music. And it was that which her father hated most.
Missy remembered her mother's piano, grand and ebony-black, with twined piano wires which created a sombre melody that filled the house when her father left for work. She used to watch her mother play, her fingers dancing elegantly across the white keys.
"This will be yours one day", she used to say to her, smiling, as she ran her hand across its smooth surface. "Do you promise that you'll look after it?"

"I promise Mama. I promise that I'll be just as good as you".

"You'll certainly be better than me, Koschei, my dear".
Then her smile dropped as she heard the door close as her husband came in from work, and she skuttled away from her piano, sheet music in hand and stuffed it underneath the stairs hastily. It was the same everyday. Until one night Missy heard shouting downstairs from her father, the sound of tearing paper and the slamming of doors. After that she never heard her mother play again when her father went to work. Her mother became reclusive, flinching whenever someone went to hold her hand and refused to go anywhere near her prized piano. Missy never knew why she suddenly stopped, or why she pulled down the sleeves of her clothing so protectively, as if she was trying to hide something from her. Only once did she ask her older sibling, Strytris, why their house was never filled with the sound of music anymore. It was a long time ago now, Missy surprised herself that she could remember it so clearly.

"Father doesn't like it", her sister answered bluntly and continued with her schoolwork. "And he gets scary when he doesn't like things".

"Scary? Why don't we tell him he's scaring mother? Maybe he'll stop".

"I can't. I really can't. And it breaks me to say it. Mother says that I can't tell him to stop or he'll do the same to me as he's done to her".

"What has he done?"

Strytris sighed. "Maybe one day you'll realise really how much of a monster he is, Koschei".

"I did... Eventually", Missy murmured then realised she was reminiscing, leaving The Doctor still waiting for her answer. Turning her head to look at him, she smiled slightly. "Any chance you can find me a piano? I've got a promise I need to finally fulfil".

"Piano? Why the piano?"

"What? Your dreams of being a two person rock band are falling to pieces?" Missy laughed and then went deadly serious. "You know why the piano".

"Hm", he hummed, realising and then held the door in his hand. "I'll see what I can do".

"Where are you galavanting now, hon?"

"Colony ship at the edge of the universe. Bill's first trip in the TARDIS".

"Ah, how sweet", Missy sneered with a fake smile. "Say hi to Dill for me".

"It's Bill..." The Doctor murmured an answer and closed the door behind him. "And you know it".

:/:
The Last of the Great Frost Fairs,
London, Britain

A fish monster. Under the Thames. Of course he couldn't just have a normal day, it had to involve corporate greed, orphans and giant, finned aliens. But Bill seemed to enjoy herself, even if the trip to the Victorian era was a little unexpected.

However now there was the slight quandary as to what to actually do with the fish under the Thames. Dowell, the tattooed ringleader of the plot to lead people to the river, was dead. Well, could be dead. Frozen perhaps. It's hard to tell when one falls through ice into the jaws of an alien fish. Bill seemed a little stunned by it all. Who would blame her? On all of her previous adventures she witnessed death and destruction. But it wasn't like they could just hide from it. For it was and is a part of the universe, of The Doctor's universe and Bill's.

"Bill. Miss Potts? I need you with me", The Doctor said with a hand to his mouth, thinking.  
"I, I..." she stuttered, pulling at the fabric of her skirt.
"Things to do, Bill. Decisions to make. What are we going to do about Tiny?"
"Tiny?"
"The creature. The loch-less monster. The not-so-little mermaid. Are we just going to leave her down there?"
"We can't set her free. She could burst up out of the water and eat a hundred people right off of Southbank! She could eat half of London!"
"She might. It's a risk. So, what do you want to do, Bill?"
"We already know the answers. Why are you even asking?"
"I don't know the answers. Only idiots know the answers. But if your future is built on the suffering of that creature, what's your future worth?"
"Why is it up to me?"
"Because it can't be up to me. Your people, your planet. I serve at the pleasure of the human race, and right now, that's you. Give me an order. Not long till noon. I need an order".
Bill paused for a moment, her curious eyes now turned serious as they darted from the ice to the people on the banks. With a sigh, she turned to The Doctor again. "Save her".
"I'll take care of this. You get everyone off the ice", The Doctor murmured a reply and took off.

Right, break the ice. Let Tiny do the rest. It seemed such a simple plan that something didn't seem right. As he ran through the streets of London, he could hear Sutcliffe's, the upper class snob that started this whole thing in the first place, voice shouting at people fleeing from the Thames. There must be something he could use to break the ice. Of course. Sutcliffe's generators. They could emit a sonic boom that would free Tiny. Market places flew past him, people looking strangely at him, but one thing caught his eye: a greying man sitting at a piano on the edge of the river bank. Taking a mental note, he continued running towards Sutcliffe's collection of tents.

:/:
"Come on! Hurry! Come on! Something's happened. They've got the word out. We blow it now!" Sutcliffe shouted at his men, getting impatient. His plan was no longer secret. The only way to protect his reputation was to remove the evidence... By any means necessary.  
"No, not yet. Harriet, run!" Bill called towards the said urchin girl.
"But there's still people..." she replied in a sombre tone.
"Forget them. There's no time. Kitty? Run! Now!"
Sutcliffe swiftly pressed the button to prime the generators and the henchmen cringed, expecting a massive sonic boom, but none was heard. "What?" Sutcliffe asked, puzzled and pushed the button again, this time to the sound of distant explosions. A wave of realisation ran over him and he seemed to turn a vibrant shade of magenta, as he stormed off across the still in-tact ice.
"Argh! Out of my way!"

On the other side of the bank, The Doctor climbed out of the well-like structure and removed his diving helmet. The reverberating noise of ice cracking sounded and the ice began to shatter. Darting his eyes across the river, he noticed the pianist sliding his piano away from the cracks in a state of panic. A scaly dorsal fin emerged from the water beneath and cut through the ice, causing crevasses to splinter away, two of which headed towards Sutcliffe and the pianist. Decisions again. Who to save? A racist living off the pain and suffering of another creature or a humble musician, risking his life to entertain others. It was an obvious choice. Though not one that he made quickly. By the time he had began to sprint towards the musician, the cracks were now just feet behind him. He looked back with terror in his eyes and gave a final push to his prized piano, making it slide across the ice. He was about to fall. And falling meant certain death from the freezing waters of the Victorian Thames. Knowing that he was close, he leaped forward, hands clinging to air, a silent prayer on his lips...
Only to find The Doctor's hand locked around his arm.
"Hold on", he said and pulled the musician away from the water then glided him across the ice towards the tents at the other bank. The musician sat, rather stunned, then turned and stood, looking towards The Doctor, who was tiptoeing away from the broken ice.

"Thank you", the musician breathed. "Thank you, thank you". The Doctor walked towards him and he immediately shook his hand. "I don't know how I can ever repay you".

"What's your name?" The Doctor asked, finding some familiarity in the man's eccentric clothing, rounded spectacles and Reading accent.

"Holst, sir. Gustav Holst", he answered and The Doctor comprehended really who it was that he had just saved from the monsterous waters: why, one of the greatest composers ever lived. What a stroke of luck! "You still haven't said how I can repay you".

"What are you doing out on the river?"

"Playing, sir. I am a musician you see. Well, aspiring. Sometimes the crowds like to hear me play piano and give a shilling or two, if I'm lucky".

"That's your piano?" The Doctor asked, turning his attention to the sleekly-built, mahogany piano sitting in the ruins of the river's market tents.

"Yes. Beautiful thing, isn't she? Though probably wasted on me", he laughed at his self-depreciation. "I'm just glad I managed to save it from the Thames. This thaw, it's... Well, it's like nothing I've seen. The sea. It's so unexplored. What if it's dangerous?"

"Ah, you humans. Always looking down. You should be looking up there", The Doctor said, pointing towards the sky. "That's where the exciting things are. Stars, galaxies, planets".

"It would make exquisite music".

"Exquisite music on an exquisite machine", The Doctor murmured, tapping his fingers across the dark  wooden surface of the piano. "Though I wouldn't know. My friend's a fan. I'm perhaps more into... Modern instruments".

"Ah, a fan of the new-fangled steel pan things, huh?"

"Uh... Yes. Something like that".

"Well then, that is your reward. Take the piano for your friend. I'm sure they would be thrilled with it. And certainly get more use out of it than me".

"She'd love that".

"Oh it's a she, is it? More than a friend perhaps?"

"We'll see. But I would hope so, maybe... I don't know". The Doctor realised that he didn't actually have any way to get it to the TARDIS. He supposed he just had to bring it to the piano. Turning his back to go, he stopped for a moment and swung back on his heels to where Holst stood. "Remember though, look up. That's where your inspiration is".

"Will do, sir!"

:/:
8pm GMT, The Quantum Fold Chamber, Earth

Sitting in The Doctor's chair, Missy licked his fingers and turned the page of a book. It was quite an enjoyable read, one about sorcerers and souls and people with funny names like Potter, but she wondered if it could have been more enjoyable if she didn't have The Master constantly narrating and adding his own footnotes. But it was quiet now, eerily quiet.

Bang
It came from the door, followed by a groaning noise. Missy didn't care, and even if she did she guessed it was Narpole or Mardole or whatever his name was trying to subtly check if the security system was working.

"Missy?" asked a voice, which he recognised as The Doctor. "Missy, can you help me please?" Missy ignored him. "Missy, I know you can hear me. Can you help me please?"

"What do you want?"

"I got you a present".

"Really?" she asked, honestly surprised. "Well, open the doors then. Lemme see it".

"I, um... I kinda need you to not run out".

"Run out? How old do you think I am, fifty?"

"Sometimes I wonder".

"I can hear you, you know?"

"Look. Can you just...?"

"Yes, dearest. I'll even stay in the containment field if you really feel that I am that flaky". He didn't answer. The two doors opened and the backend of a dark brown, almost black piano came through. "Oh... Wow", Missy breathed, nostalgic thoughts of her mother's piano filling her mind.

"Thought you'd like it".

"Where the hell did you get this?"

"Victorian London... From Gustav Holst of all people".

"Wait, the one who composed The Planets?"

"Didn't know you were into classical Earth music, Missy. Wouldn't take you for someone who was". Missy scoffed, realising she had given herself away.

"I've been here a while. It's not like you'd given me anything else to do". The Doctor pushed it into the containment field and sighed. "Is that supposed to be incentive for me to go in there?"

"No comment", he murmured, finding a stool from the room and gestured towards it. "All yours".

"You're a dear, you know that?" she said, putting a hand to his cheek and sitting down by the piano. Running her hands down the keys, she found her place and started to play, a wave of memories rushing over her as the notes to the song that her mother used to play reverberated through the piano. The Doctor watched on, the sombre melody of Missy's childhood lingering in the air like a kiss. And though they were silent, they were content. In their shared happiness and the sound of piano notes.