With everything she had once thought she understood spinning before her eyes, Jasmine found herself preferring to take her chances outdoors. She squeezed out through the window and made a watchful dash back to the shadows under the walls of her own house, alert for any sound of metal giants approaching. It was quiet. She rounded a corner and almost ran straight into the Doctor.

With a squeak of alarm, she jumped back and eyed him warily, but he just stood motionless, watching her with his pale, weak eyes, leaning on his stick with both hands, wrapped as she had seen him a thousand times before in his shapeless black hat and overcoat, which merged into the darkness of the night. Countless questions, none of which made sense, buzzed in her mind, and all she could do was point desperately at the mansion behind her.

"In the house. Metal men..."

"Yes." The old man's dry, cracked voice was calm and quiet. "I saw. I think the servants all got out the back way. Where's your guardian?"

"He's still in there!"

The Doctor turned his head towards the mansion, his face immobile.

"He saved me!"

He grimaced, and looked down at the ground, his fingers fidgeting on his cane and the lines on his face furrowing deeper in thought.

"Well," he murmured, "We'll see." His gaze fixed on her once more. "Do you still have the thing you found on the beach?"

An instinctive twitch of her left hand drew his eye to where she had kept the metal disc clutched all this time, its edges digging into her flesh.

"Hand it over," he told her. She didn't move, and he sighed. "Jasmine, it's emitting a hypertronic pulse which interacts with your brainwave patterns. That's why you picked it up in the first place and why you don't want to give it away now. It also emits a secondary pulse which those creatures can track. You understand? They know exactly where you are right now. If they haven't come after you yet that means they're betting if they stay quiet you'll eventually go back. That's when they'll grab you."

Jasmine shuddered, the image of the looming, unstoppable, faceless creatures fresh in her mind, but still hesitated. To hold on to the disc felt so right.

"I could hypnotise you, you know," the Doctor said softly. "But to save your guardian I think you'll do this of your own accord."

She saw again pompous, stuffy little Mr Heffer throwing himself at the two monsters with a poker clutched in his plump hands. Before she knew it the Doctor was plucking the mysterious circle of metal from her outstretched palm.

"I couldn't believe it," she said, as if what she had just done was wrong and she had to explain it. "What he did. He was so... heroic."

"Yes. He was probably as surprised as you. That's the trouble with humans. Never know which way they're going to jump until the time comes. And then of course, it's too late."

Moments later, the two of them were slipping into Heffer's study. It was dimly lit by the gas lamps, but deathly quiet. Wheezing a little from the effort of keeping up with Jasmine, the Doctor hobbled over to the electricity generating bicycle, standing unattended in the corner.

"Right..."

Just then a protesting creak of floor boards from the other end of the house warned of the approach of something far heavier than any man. The Doctor tensed, and spoke quickly, his voice hardening.

"Get on the bicycle, Jasmine. And pedal for your life."

"What?"

"Just trust me. I used to do a lot of this sort of thing."

Another weighty footfall, much closer this time, was all the persuasion she needed. Jasmine clambered onto the machine, dragging her unwieldy skirts out of the way of the wheels and cogs, and forced the right pedal down, standing on it with her full weight just to get it moving. Meanwhile the Doctor leaned against the wall, dropping his stick and prising the metal disc apart with his fingernails, talking as he worked.

"There's a great deal of technology packed into this device, and it's designed to keep operating for a long time on a very limited amount of stored energy. That means its power output is extremely low, and that in turn means that to pick up its signal clearly over long distances and through solid objects these things we're facing have to amplify that signal to a very great degree. So all it will take is a fairly minor power surge on the right frequency to blow their receivers and, with any luck, a lot of other vital equipment at the same time. All we need is a little bit of electricity."

He whipped a pair of thick glasses from his waistcoat pocket and, while putting them on, glanced up to see Jasmine straining desperately to keep the heavy dynamo turning at a painfully slow pace.

"Jasmine," he said, quietly but very seriously, "You have to pedal faster than that."

She shifted her grip on the handlebars, using them to drag her weight downwards, well aware that her guardian's servant, twice her size, had needed all his strength to power a single light bulb from this same machine. She strained with everything she had, and then the study door, not ten feet in front of her face, was ripped intact from its hinges by a single gigantic gauntlet. The iron monster stalked into the room, the glowing circle that served it for a face shining a painful white light into her eyes.