Riding to the Past

The Doctor stared in amazement as his companion pulled a face as she sailed past on her black stallion. The Doctor's own gentle dappled mare tossed her head in retort, and he patted her absently. He knew now why Ace's face had lit up at his suggestion of going back to medieval England- they rode horses everywhere. But he had no idea just how much of a natural she was with the equine species. He snapped out of his personal thoughts as a second horse trotted to his side. The rider called out to him.
"I say, Doctor. Young Ace seems to be getting on rather well, doesn't she?"

He turned to face the man who had spoken. "Yes, she is. I think I'll catch up with her, if that's all right with you, Arthur."
The man nodded. "Whatever you wish."
As the unusual little man with the duffle coat cantered after his young friend, Arthur shook his head. "Maybe I should ask them to join the ranks of my knights- the way the young lady dresses, no-one would know she wasn't a man."

Meanwhile, the Doctor caught up with Ace as she reined her exhausted horse in. As the mare slowed to a stop, she grinned at him.
"Not bad for a girl, am I Professor?"
He grinned back. "I never said you weren't. Where did you learn to ride?"
She shrugged. "Can't remember. Stables just outside Perivale, I think. It was ages ago. Hey!"

Ace's last word caught his attention, and he followed her gaze. Speeding towards them was a sleek silver sports car, hurtling down the rough cart track. The Doctor's mind started to whizz. A sports car? In this time period? His thoughts were sharply broken as his mare started to buck. He stole a glance at Ace, and saw her stallion doing the same. They were obviously spooked by the car- and rightly so, he thought to himself. He pulled on the reins desperately, trying to sooth the frightened horse at the same time. It didn't seem to be working, and as the car thundered past them he felt the mare buck with full force. He was caught unawares and was thrown onto his back on the ground. Severely winded, he saw two things from the corner of his eye- Ace had managed to stop the stallion from repeating the mare's actions, and he could vaguely see Arthur's horse coming in from the distance. As Ace dropped to her knees next to him, his vision blurred. He was slipping out of consciousness, but he vaguely heard Ace's last sentence.
"..fessor! Professor! Can you hear me, Profess..?"