Dean looked at his brother and shrugged, then muttered, "C'mon, Sammy", and took off after the Doctor, who was running, surprisingly fast and agile.

Sam glanced over his shoulder, and could just make out the shape of the creature against the night sky, illuminated by the light from the exploding cars. It was huge, black and simply terrifying. I mean, Bobby had said there had been reports of a big monster in the town-but there was big and then there was HUGE.

The Doctor skidded to a halt in front of a small convenience store, and spun around. "Er-I need you to wait here for a second. I'll be right back" he said, sounding harassed, then sprinted off behind the building.

"Where the hell are you going?!" Dean shouted, then shut up as soon as the creature roared, evidently having found out its' prey had escaped. "Shit!" Dean said loudly, then opened fire on the creature with his rifle, while Sam joined in with his revolver. However, the bullets were no use: they simply bounced off the monsters' scaly hide. Dean threw his rifle down in exasperation.

"Damn it, Sammy!" he exclaimed, then glanced at the creature, which seemed to be lumbering uncertainly in their direction, as if blind. Dean threw his rifle down in frustration.

This is it, Dean thought to himself. He always thought he'd die in battle somewhere, after courageously saving young maidens and taking down as many demons as he could, not at the mercy of a creature with only the help of a man that looked like a university professor to rely on.

"Dean, what's that noise?" Sam's voice shook Dean out of his internal monologue, and frowned at his brother.

"What noise?"

"That one. Can't you hear it?"

Dean concentrated. Yes, actually, the sound was getting clearer by the second. It was a strange whirring, metallic sound.

And then, before their eyes, a blue box materialised, and landed with a loud thump. The door opened quickly, the hinges creaking in protest, and Dean privately thought they could do with a good oiling.

The Doctor jumped out of the box and clapped his hands together. "Hello, boys! Glad to see you're not dead. Right, well um-have you been using guns?!" The Doctor looked positively outraged.

Dean opened his mouth to reply, undoubtedly angrily, when the Doctor snatched the rifle up off the ground, then took the hand gun away from Sam. "No guns around me!" he said sternly.

"Um, excuse me, you assbutt, but who do you think you are? You've got no business taking away our weapons."

"Er, yes I do, actually. Now, please step inside, before we get stood on by the rampaging alien."

"Alien?!" This time it was Sam.

"Yes, alien. It's ship crashed in San Francisco and I've been tracking it for days. Now get in the TARDIS!"

The boys stepped inside and the most amazing sight met their eyes.