"Wait! What about the Doctor?" Rose shouted, digging her heels in to force the Master to stop. She could see the Tardis in the distance, like a beacon of hope.

"What about him?" the Master asked, irritation lacing his words.

"We can't just leave him!"

The Master huffed in annoyance. "He's coming along. Should be here any minute now."

Rose frowned. "How can you tell?"

"I can sense him. You can, too, if you concentrate on your bond with him," the Master stated, poking her forehead.

"I, uh, have no idea how to do that."

The Master rolled his eyes and muttered something under his breath. She thought she heard the phrase 'stupid primitive humans', but couldn't be sure. Rose placed her hands on her hips and glared daggers at the Master.

"I haven't been trained in these things, okay. So you can stop your insults before you find a foot up your ass!"

The Master flashed her a wicked grin. "I'd like to see you try, Rose." His face became serious as he glanced behind her. "And it looks like the Doctor is right on time. Isn't that something?" The Master paused. "Hmm, seems he bought along some company."

Rose glanced over her shoulder and her eyes widened when she saw the Doctor sprinting for all he was worth towards them, an angry mob of Doncoonians hot on his heels.

The Master grabbed her hand and shouted, with far too much glee, "Run!"

Rose glanced back to make sure the Doctor was right behind them before taking off towards the Tardis. She slammed into the door and fished out her key from the silver necklace around her neck, her hands shaking as she tried to insert the key into the slot.

The Master snatched the key from her hand and had the door opened in a second before roughly shoving her into the interior. Rose whirled around and felt immense relief when the Doctor bolted in and the Master shut the door firmly behind him, which was followed by numerous thumps as the horde slammed into the door. The Doctor didn't pause for breath as he raced to the console and dematerialised the Tardis.

There was a few moments of silence as each tried to catch their breath.

"Well that was quite an enjoyable trip. Let's do it again!" the Master enthused, his eyes sparkling with wicked delight.

"What did you do?" the Doctor demanded, straightening up and giving the Master his Oncoming Storm glare.

The Master shoved his hands into his pant pockets and ambled over to the console. "Oh, I just blew up their prison."

There was a stunned silence. "You could have hurt some innocent people!" the Doctor bellowed.

"Pft. It's a prison. How many innocent people do you think are in prison?"

"It doesn't mean that they deserved to die!"

The Doctor looked as though he wanted to throttle the other Time Lord. The Master, on the other hand, was the epitome of cool and collected, with a dash of sadistic enjoyment at causing the Doctor so much ire.

Rose decided it was time to intervene.

"Master, was the prison empty?"

The Master pursed his lips as he made a show of thinking about that question. "Mostly," he eventually replied, drawing out the word.

"So…how many were in there then?"

The Master turned his attention skywards and ran his tongue over the front of his teeth. "Hmm. Difficult to say. Probably a few hundred."

The Doctor's eyes bulged out and he clutched at his hair with both hands. If he were human, Rose was sure he would have keeled over from a heart attack.

"You just killed a few hundred people!"

A slow, lazy smile bloomed on the Master's face. "Did I now?" he asked in a far too innocent tone.

Rose sat down heavily. This was not good. She had been vouching for the Master to have been reformed somewhat, but this act of his just proved that he, indeed, was not. Her heart ached at the thought of him becoming a prisoner in the Tardis; too volatile, dangerous and unpredictable to be let out.

"Master, how could you?" she whispered.

"What? They were the scourge of the planet. I say good riddance. Anyway, there's more where they came from."

The Doctor was now pacing back and forth, his hands running through his hair and mussing it up spectacularly as his agitation grew in intensity.

"Problem is," the Master continued, examining his nails, "it's hard to eradicate Calpimons. That prison was infested with them, and I daresay I didn't get them all."

The Doctor instantly stilled and slowly turned his head to stare at the Master, a look of pure astonishment on his features. "Calpimons?" he croaked.

"That's what I said, you moron," the Master snapped. His eyes flickered to the Doctor and his smile widened. "What did you think I was referring to?"

The Doctor opened and closed his mouth, words for once eluding him.

"What are Calpimons?" Rose asked.

"Earth's version of cockroaches. Only Calpimons are the size of your hand and hairy and have a nasty bite," the Master said in a bored tone. He then shot Rose an exaggerated wink before strolling out of the console room, humming a tune that sounded distinctly like the theme song to Teletubbies.

"Well…that's good I suppose," Rose mused aloud. "At least he didn't kill anyone."

The Doctor bent over the console, gripping the edge tightly that his knuckles became white. He bowed his head and inhaled deeply.

"Doctor? What's wrong?" Rose asked, instantly at his side and touching his arm tentatively.

"I think the Master is going to test me to my limits. And it doesn't help that I'm not particularly patient in this regeneration."

Rose chewed her bottom lip to stop the smile that was threatening to break through. Oh yes, the Master was very intent on giving the Doctor a hard time. And by the looks of it, he was succeeding.

The Doctor straightened and ran a hand through his wild hair, a deep sigh escaping his lips.

"Fancy watching a movie?" Rose asked, nudging his shoulder with his. Best to try and keep him occupied.

"Actually, that sound like a great idea," he said, his face alighting with enthusiasm as he grasped at the distraction Rose was offering.

"I'll make the popcorn," she said, walking to the kitchen. Rose paused and addressed the Doctor sternly. "And don't pick Mary Poppins again."

"But Rose," he whined. "It's a classic."

"It was the first ten times we watched it. You have now killed the magic of it for me."

The Doctor pulled a face. "Fine, but I refuse to watch any of those soppy romances that you are so fond of. So predictable and so boring. And did I forget to mention unoriginal and the plot lines mediocre…" he rambled as he followed her to the kitchen, his earlier consternation at the Master forgotten.

ooOoo

Two movies later, Rose stretched and yawned.

"I think it's time for me to hit the sack," she declared, standing.

"Yes, you look beat," the Doctor said a bit too enthusiastically.

Rose smiled down fondly at him. "You're going to watch Mary Poppins, aren't you?"

"Who? Me? Wouldn't dream of it!" he stated quickly, his voice going slightly higher in octave.

Rose shook her head, the smile never leaving her face as she bent down to give the Doctor a peck on the cheek. "Okay, well you enjoy Mary Poppins. See you in the mornin'."

"There's no morning on the Tardis, Rose," he called after her as Rose exited the room.

The smile vanished from her face as soon as she left the room, and Rose walked with determination to the Master's bedroom. She paused outside the closed door and then lifted her hand and gave a small knock.

"Come in, Rose," the Master called from the other side, his voice slightly muffled by the barrier.

Rose swung open the door and walked in, unsurprised to find his room back in order and all traces of destruction erased like a bad dream. She closed the door softly behind her and turned to face the Master, who was sitting at his desk, fiddling with some sort of contraption. He didn't bother to glance up as she made her way to him.

"So, did you find what you were looking for in the prison?" she asked casually, running her finger along the smooth, varnished wood of the desk.

The Master looked up to peer at her through his lashes and slowly sat back in his leather bound chair. He folded his hands casually over his lap and raised a brow.

"What makes you think I was looking for something?" he drawled in an almost bored manner, though his eyes were sharp and calculating.

Rose gave him a sly grin. "You suggested that we go to Doncoon. You also happened to mention that you were once imprisoned there, and I find it highly coincidental that you blew up the prison after being gone for over an hour."

"That's a lot of theorising," he said drily.

"So did you find it?" she pressed.

The corner of his mouth curved up. "And what was I supposed to find?"

"You tell me," Rose challenged, leaning forward so that she was eye level with him over the desk, her palms firmly planted on the surface of the desk.

The Master chuckled and shook his head. "Say that I did hide something there and went back to retrieve it, what makes you think I would tell you?"

Rose straightened. "I didn't expect you to tell me what it is you went to get, but you have basically confirmed my suspicions that there was something." She shot him a mega-watt grin and made to leave.

"Rose?"

Rose halted and glanced over her shoulder.

"Don't tell the Doctor."

Her face softened and turned in her spot to give him her attention. "The Doctor's going to figure it out soon, if he hasn't already. Is it something bad?"

The Master leaned forward and clasped his hands in front of him on the desk. "No. It could be dangerous, though," he teased.

Rose studied him for a moment and then came to sit on the chair opposite the desk. The Master raised his brow questioningly.

"Can I ask a favor?"

The Master's face transformed to a stony cold mask. "And if I refuse, you'll what? Tell the Doctor of my escapade?"

Rose scoffed. "Don't be daft, you dunce." Her voice softened as she continued. "We're all entitled to our secrets. That's actually the reason I'm here."

"I'm not following."

"I want you to help me with my mental shields."

The Master frowned. "Why don't you just ask your beloved Doctor?"

"I don't want him poking around in my mind and coming across my secret."

A devious grin spread on his face. "And you trust me not to break that door down and find out myself? I could easily do it – I could make you spill all your dirty little secrets."

"So why haven't you," she asked, cocking a brow and crossing her arms over her chest.

The Master hesitated, and Rose gave a triumphant grin.

Rose leaned forward, mirroring the Master and said in a low voice. "You would have done so by now, if you really wanted to. So why haven't you?"

The Master glared back at her. "Because for once, I have found something I wish to keep and I don't want to jeopardise that."

Her face softened and Rose took his hands in her own. "I trust you, Master. You knew about my secret and you kept it, and I know you will continue to do so. That is why I am asking you."

His thumb rubbed a lazy circle over the back of her clasped hand. "You know, sooner or later you're going to have to tell me what you big bad secret is."

Rose let out a sigh. "I know…but not now. I can barely face the reality of what I did. I don't think I could bear the look of judgement on both yours and the Doctor's face when you two find out."

The Master snorted. "I am the last person qualified to judge."

Rose gave his hand a squeeze and stood. "That's why I know I can trust you with this."

"And what do we tell the Doctor? He is going to get curious as to why we're spending so much alone time together. He might even jump to the wrong conclusion." An evil smile spread across his face, his eyes alighting with anticipation at this thought.

Rose rolled her eyes. "Yeah, you really need to lay off of him. That little stunt earlier caused him to age a decade or so."

His eyes glinted wickedly. "I told you, Rose, I don't plan to make this easy for him. But you haven't answered my question."

Rose bit on her bottom lip. "I don't know what excuse I'm going to tell him. I don't like lying to the Doctor, but I want to keep this from him. You know how the Doctor is – he'll be persistent."

"Yes, the Doctor likes keeping his secrets, but hates it when others keep stuff from him," the Master said with an edge of bitterness.

"So will you help me?" she asked, her voice sounding unsure.

The Master drummed his fingers against the desk. Finally he nodded. Rose's face flooded with relief.

"Thank you," she whispered.

"Don't thank me yet, Rose. I have a feeling this is going to backfire spectacularly."

"And you'll enjoy every moment of it."

"Of course I will."

Rose gave him an indulgent smile and left. The Master sat back in his chair and steepled his fingers in front of him, a thoughtful look creasing his features. Rose had been right – he had gone to retrieve something from the prison; something he had hidden exceptionally well in his old cell. And right now it was embedded in the bracelet he had given her. It was highly deceptive of him, but he was not sorry in the least.