Clara and Porridge watched Angie and Artie float in the anti-gravity space.
"Whoa!" Artie exclaimed.
Clara aimed her phone at them. "Smile! Say, 'Spacey Zoomer!'"
"We're flying!" Artie said.
"Having a good time?" the Doctor asked, floating down beside them. He laughed and the kids laughed with him.
Porridge turned off the anti-gravity and the three of them floated gently to the ground. Clara walked toward them.
"I think that was the most fun I've had in my whole life!" Artie said.
"It was . . . okay," pre-teen Angie said.
The Doctor leaned over her, making a face. "Okay? Okay?! Come on." He grabbed her under her arms and flew into the air.
"Hey! Put me down!" she shrieked.
After a moment she calmed down, knowing she didn't want to fall from so high. The Doctor carried her higher and then dove. He sped up and curved upward again. He swerved to the side and twisted and dived through the air, taking Angie on a ride unlike any other. After a few minutes, the Doctor glided to the ground and set Angie on the ground. Her hair was a complete mess and she looked both terrified and exhilarated. She steadied herself, letting her legs adjust to being on the ground again.
"My turn!" Artie shouted, running at the Doctor.
"Actually, there's a thing that needs to be done," the Doctor said, turning away and pointing abstractly. He started to walk away, but Artie latched onto him. The Doctor sighed. "Fine. Okay. When we get home I promise to give you a ride," he said, turning around, "But right now I've got some important sonicking to do," he said, flipping the sonic screwdriver out of his pocket.
Artie reluctantly let go and the Doctor walked away, scanning the area.
"Oh... this is brilliant!" the Cyberleader said through the Doctor's body, "I'm so clever already, and now I'm a million times more clever," he said as he spun across the room, "And what a brain! Not a human brain, not even slightly human," he said, looking at Weebly in disgust. He leaned against the table. "I mean, I'll have to completely rewrite the neural interface, but this is going to be the most efficient Cyber-Planner!" he exclaimed, jumping onto the table, his arms spread, "Not a great name, that, is it? I could call myself Mr. Clever." He gasped. "Ooh, what's this?" He floated gently off the table and flew for a moment before falling slowly. He flapped his arms, but fell to the ground. "He can fly. The Cybermen can't. He can teach us. How does it work? This upgrade is going to take a while. So much raw data . . . . Time Lords. There's information on the Time Lords in here! Oh, this is just dreamy!"
"Chess game . . . . Stakes?" Clara asked.
"If he wins, I give up my mind and he gets access to all my memories, along with knowledge of time travel and the ability to fly. He's already working on that last one, but Cybermen can't fly unless they have imagination, free thought, and individuality. If they develop imagination, free will, and individuality, they will become the most dangerous creatures in the whole universe and life as we know it will be over."
"And what if you win?"
"If I win, he'll break his promises to get out of my head and then kill us anyway."
"That's not reassuring," Clara stated.
"No, but at least they won't have the power to fly, imagine, think freely, or be individual . . . as long as I get him out soon enough."
"Please tell me you can fix what happened to the children," Clara said, changing the subject.
"What's that cable?" Clara asked.
"Power line for the park," Porridge answered.
"What'd happen if we dropped the end into the moat and turned it on?" Clara continued.
Ha-ha smiled. "Fry anything that entered the water."
"Do it," Clara ordered, "At least it'll work until they figure out how to fly," she added under her breath.
Clara and the soldiers watched the Cybermen advance on the castle, stopping at the electrically charged moat. One stepped forward and with a light hop and a flap of its arms it flew into the air. Clara watched in horror as it floated over the moat.
"They can't fly. They've never been able to fly!" Porridge said, horrified.
The flying Cyberman suddenly shuddered. "Upgrade incomplete," it said just before it exploded.
Clara let out her breath.
"What was that?" Brains asked.
"What are you not telling us, Clara?" Porridge accused.
Clara contemplated before responding. They watched another Cyberman step into the moat and jerk violently, sparks flying from its metal body.
Clara cheered. "Brilliant!"
"Clara . . . ." Porridge pressed.
Clara sighed. "You deserve to know. You saw the Doctor flying. The Cyberleader is in his head. It's using him to learn how to fly. Flying takes imagination, free thought, and individuality. If the Cybermen develop those things in their quest to fly, they will be the most deadly force in the universe. But you saw what happened. They can't do it yet. We still have time."
The Cyberman in the moat straightened. "Upgrade in progress," it chimed. The Cyberman resumed crossing the moat and the others followed.
"Okay, slightly less time," Clara said. She looked at the soldiers. "Who's our best shot?"
"What are you doing?" the Doctor asked, horrified.
"Doctor," the Cyberleader repeated his name over and over teasingly, "I'm pulling in extra processing power. Three million Cyberbrains are working on one tiny chess problem. And you've been teaching us imagination and free thought. How long do you think it's going to take us to solve it?"
"That's cheating!" the Doctor exclaimed.
Artie whooped and yelled as the Doctor took him on a wild ride in the sky. They gently descended to earth and the Doctor set Artie on the ground. Artie shouted with excitement and ran and hugged Clara.
"Whoa! Hey! Artie, remember your manners," Clara said.
Artie ran back to the Doctor. "That was definitely the most fun I've had in my whole life!" He sobered and presented his hand.
The Doctor shook it.
"Thank you for having me," Artie forced himself to say, "It was very interesting."