"Dan?"

Dan and Zoe skidded to a stop and pulled out their communicators so they could hear Tom as he said, "The power unit's blown. I need . . . half a million bolts to power this thing."

Dan and Zoe both looked up as they heard thunder rumble outside, the lighting sending strange shadows across their faces, making their skin appear white.

"It's the thunderstorm." Dan said, looking out the window as the cogs turned his head.

"Nice job, Sherlock." Zoe muttered. Dan turned to look at her and then noticed the frame hanging on the wall behind her – the science project the first students at St Heart's had done. The one where they studied how much electricity was in a lightning bolt.

"I've got an idea." Dan said, glancing behind him as Frank yelled out, again reminding the blonde of a rabid dog. Dan dragged Zoe into a corner, pushing her into the wall and shielding her with his body. Zoe's eyes flickered up to meet Dan's before he moved back to see where Frank was – not too far out that Frank could see him, but far enough that he could see Frank. Frank, making noises that human vocal chords weren't designed to make, ripped the poster advertising the party going on, off the wall.

Dan turned back to Zoe, staring into her eyes as he said quietly, "But this idea would mean you getting Frank back to the hatch on your own."

Dan turned back to see what Frank was doing and saw him turn a bin over, scattering rubbish everywhere. Then Dan turned back to Zoe, leaning against the wall. "What am I thinking? Forget it."

Zoe grabbed his wrist and pulled him to face her. "Dan, we've got no better ideas. I'll do it. Do what you have to."

Dan stared down at her. "I can't lose you, Zo."

Zoe gave him a small smile. "You won't. I'll be fine."

Dan nodded and brushed her hair back from her face, letting his hand linger on her cheek. "I know you will."

Zoe noticed the regret in his eyes and took his face in her hands. "This isn't your fault, Dan. You couldn't have known – "

"This is entirely my fault." Dan said. "If Frank kills someone, if he kills you . . . the responsibility will be completely mine. As it should be."

Zoe pressed her mouth against his quickly before she drew away. "We don't have the time to talk about this now. None of this is your fault, okay? I love you."

"I love you." Dan murmured as Zoe tugged her dress down and muttered, "This is the last time I wear a short dress to impress you."

"This is the only time you've worn a short dress to impress me." Dan said, his gaze raking over her body. "You should do it more often though."

"Don't count on it." Zoe replied, brushing past him to stand in the middle of the corridor. She crossed her arms over chest as she waited for Frank to notice that she was there and when he didn't, she stamped one heeled foot against the hard floor and yelled, "Hey!"

Frank looked up, muttering incoherently as Zoe said, "You with the attitude problem."

"Destroy." Frank said and started after Zoe. As Zoe turned and stumbled through the doors, she had a flashback of something that had happened only a year ago in this very corridor.

Zoe, her face hidden behind a green silicon mask that stank like plastic, crept up behind the big man in black as Aneisha edged towards him, the big brown bag in her hands. As Aneisha passed the man the bag, he pushed someone forward and a tall boy with a mop of blonde hair grunted, stumbling away from him as he tended to his sore arm.

"I would love to stay and chat." The man said, adjusting the straps on the bag. "But I really must get this valuable box back to my bosses."

Then he turned, coming face-to-face with Zoe as she raised her hand, holding a device that glowed blue as she pointed it at him. The man reached out for her with one hand, but then he froze as a blue pulsing aura seemed to surround him. When both he and the device stopped glowing, he fell to the floor, snoring softly.

Zoe pulled her mask off as she walked over to Dan and Aneisha, who were both watching the man who had spent the past few days pretending to be somebody he wasn't as he slept.

Aneisha knelt down beside the sleeping man as Dan and Zoe stood side by side behind his head.

"Nimbic stimulator. I've got your back too." Zoe said to Dan, holding a hand up. "High six?"

"Five." Dan told her, high fiving her.

Zoe smiled at the memory, her pace slowing slightly, but hearing Frank muttering behind her, she took off again. Dan watched her go before he took off the other way, his coat flying out behind him. He found Mr Flatley, Preston and Roly as they stumbled outside after he'd found two big, heavy cables. He could hear Mr Flatley laughing and then he heard him exclaim, "The chance to study an actual lightning bolt! Preston! Roland! Prepare the machines!"

Both boys did as they were told and Dan looked up at the tower before he ran towards it, clipping one of the cables onto it before he ran off with it, the other one coiled around his shoulder. When it pulled taut, yanking his whole body back a few steps, Dan dropped the cable and sprinted over to the hatch with the remaining cable.

"Tom!" Dan shouted down his communicator once he was standing in front of the hatch. "I'm sending down the cable!"

Then he threw it down, listening to it banging against the walls as gravity pulled it down.

"Got it. Hooking it up to the cage." Tom said. Dan looked up as he heard the unmistakable sound of Zoe's heels clicking against the pavement as she ran towards him and he hid behind a nearby garden.