The Master opened his eyes and found he was pressed against someone's chest and the owner of the chest was stroking the top of his head. "Mm, that feels good... Huh?" he managed, trying to look around him. When no danger presented itself for the moment, he closed his eyes again, relaxing under the ministrations of the hand.

"So that's the Master?" a voice that the Master recognised as Martha Jones asked. "He's so cute."

"Yup," the Doctor answered, popping the 'p' loudly.

'Have I regenerated again?' the Master wondered. He opened his mouth to tell Martha what a stupid ape she was, but all that came out of his mouth was an indignant miaow. His eyes flew open. 'Did I just...?" He looked down at his body and noticed he was in a very undignified pose. Luxurious black fur covered his stomach, four black furred limbs were sticking up in the air and a long black tail was waving hypnotically in front of his face. 'What the Hell?' He squirmed as Martha ran a finger on his stomach and couldn't quite stop the purr that escaped his throat. 'No! That's Martha Jones, the human that ruined all your plans. You hate her... Oh, that does feel nice...'

"Why a cat, Doctor?"

"Well, you know how cats are. Isn't he adorable?"

"Yes, but if he's going to be a space faring cat, he'll have to go to the vet first."

"Why?"

"To have all his shots and maybe get..," Martha answered, making a snipping motion with her fingers above his stomach.

The Master realised where Martha was going with that comment, and what she was trying to say, and wriggled in the Doctor's arms. 'No! I won't let her! She's mean!' He glared at Martha and let out a loud hiss that ended in an unearthly yowl which conveyed his feelings on that matter plainly. His tail swished angrily.

"Martha! Not in front of the Master!" the Doctor protested, trying to calm down the Master in his arms. He yelped as the Master practically scrabbled up his arm and clung on to him with sharp claws.

"Fine! But if he starts marking his territory, you clean it up. He will needs his shots though. Can't have him catching anything, can we?" Martha stated in a no nonsense tone of voice as she gave the Master a stroke on the top of his head.

"No, guess not," the Doctor answered, pleased that Martha seemed to enjoy their impromptu pet.

The Master got the feeling that if he put a paw out of line, Martha would carry out her unspoken threat and decided to try and behave. He managed a catly smirk. Behaving doesn't mean that he had to get along with her though. Even though she was good at the stroking thing.

"Besides, cats seem to regard humans as their minions anyway," the Doctor pointed out. "Not much of a change from his usual self."