A/N: This very AU scene resulted from a challenge issued by lost_spook/vvj5 for a fic that I would never write: Jo decides she's had enough of Three and goes off travelling the universe with the Master, who she's always secretly preferred anyway.
This is the result, though now I feel a little guilty about it - poor Three.
Worlds of Betrayal Between Us
"Are you ready, Miss Grant?" the Master purred, his TARDIS standing ready in the middle of the room.
The Doctor snatched at his assistant's arm. "Jo, I can't let you do this! He's a…a criminal!"
She looked up at him and laughed, but it wasn't her usual laugh; it had a cruel edge of mockery he'd never heard from her before. "You can't stop me. I've had enough of this ridiculous lab, and your ridiculous patronizing chauvinistic… ooh!" She yanked her arm out of his grasp and turned to the Master, coyly draping her hands over his black-clad shoulder. "The entire universe is out there, Doctor, and you won't show it to me, so I've found someone who can."
The Master smugly raised his chin. "Face it, Doctor, I've won. Why did you think I always knew where you and Miss Grant were going to be? Why did you think your little plots and plans always seemed to work out? Did you think it was you?" He chuckled. "I'm far too clever to allow myself to be limited by the quaintly bucolic wishes of the High Council."
"You've hypnotised her, haven't you? Jo, come here, listen to me…" the Doctor snapped his fingers.
Jo shook her head. "Oh, I'm so hypnotised," she said sarcastically and put out a fingertip to stroke the Master's goatee with a little pout. "Aren't I, you evil thing you. It was quite naughty of us to trick the poor Doctor wasn't it?"
"Poor Doctor," the Master agreed silkily. "You see, I'm a connoisseur of all the finest things the worlds out there have to offer, and Miss Grant is….very fine. After you, my dear. I've a world we'll make you Queen of, and then an Empire sadly in need of a new Empress."
"I love it when you talk that way," she smiled and gave the Doctor a little wave. "Do tell the poor old Brigadier goodbye for me," she said. "Enjoy your little cage."
With the sound of Time being ground in its gears, the Master's TARDIS faded away. And the Doctor, though dry-eyed, wept.