NB: My portrayal of Romana may be awful. If you feel this way please feel free to kick my butt.

DOCTORWHODOCTORWHODOCTORWHODOCTORWHODOCTORWHODOCTORWHO

Before anybody could say anything else, the TARDIS lurched so violently that it was practically horizontal. Romana, the Doctor and Harry had collided, very painfully with the opposite wall into the wall. Sarah had managed to grab onto the edge of the console, until there was an explosion and the room started to fill with smoke. Then she whizzed backward into the wall, protecting her head with her hands.

The Doctor struggled forward and managed to get the ship back under control, and everyone righted his or her self, albeit through very thick smoke.

"I say, Doctor, what happened there?" Harry choked as he stood up.

The Doctor's reply was slightly muffled, as his face was buried in his scarf. " This planet we're going to has very high security systems, and they affected the TARDIS."
"How did they affect the TARDIS? And why are we going here anyway?" Romana said, tucking her blonde hair behind her ear.

"Well, they are very strong devices, and they scrambled the TARDIS' brains, is the simplest way of putting it?"

A "Know how she feels" came from somewhere to his right. Obviously Sarah wasn't best pleased at almost getting her head split open.

"And we are going to this planet to discover why a recent acquisition of a crystal from another galaxy is affecting the population of this planet."
"Well, why did you call us back for that?" Sarah said.

"Well I thought you and Harry might enjoy this sort of thing."
Harry shot a look at Sarah. "Where did he get that impression?" he whispered.

"Don't ask me," she whispered back.

With its usual wheeshing sound, the TARDIS landed, and the four stepped out.
"This place is completely deserted," Harry said.

"Very well noticed, Harry,' the Doctor said without turning around. "But I must warn you all. These machines will do anything to break down your spirit if they think you are intruders."
"And you think we'd like this sort of thing?" Sarah said, incredulously.

They walked on until Romana vanished down a hole.

"Romana?" The Doctor turned round so fast that Harry and Sarah had to duck to avoid getting hit by his scarf. Sarah's sharp eyes noticed the rapidity with which he turned round.

"I'm down here." her voice came floating up from a hole. "There's a slide down to it!"
"Oh well!" The Doctor jammed his hat on his head, and vanished. Harry went next, and when Harry said it was safe to come down, Sarah steadied her nerve and pushed herself down the pipe. It was a fast ride to the bottom, with cool air rushing up into her face, and she rolled out at the bottom to be reunited with the rest of the group.

The Doctor spotted a door further along and motioned Harry, Sarah and Romana to come over.

The room was completely deserted, but a podium held a strange white object in a ray of light.

"Is that the crystal?" Romana whispered.

"Certainly is," the Doctor replied, not taking his eyes off it.

"How can a thing like that alter the mind of the entire planet?" Harry said, with a tone of puzzlement in his voice.

"I'm not sure, Harry." The Doctor was thinking. " How are we going to get inside?"
"Use your sonic screwdriver, perhaps?" Sarah suggested.

"Good thinking!"

The screwdriver buzzed, and the door swung open with a click. They stepped inside. Suddenly Sarah heard something moving along the corridor.

"Doctor," she said, the shaky tone that always crept into her voice when she was nervous coming back, "I can hear something moving out here."
So could everyone else. Romana spotted an alcove where they could hide, and quickly directed everyone into it.

The Doctor, Romana, Harry and Sarah stood as quietly as possible, as the voices crept nearer.