In Ianto's arms, Jack barely startled at the sound of the alarm that accompanied the opening of the cog door. Honestly, Ianto felt sorry for him all the same. If cat ears were as sensitive as he'd heard, the alarms would be far too loud for Jack.

'Ianto!' Gwen greeted. 'You're back!'

'Can't keep me away, ma'am,' Ianto replied, heading down into the medical bay to where the Doctor was working.

'Ah! Mr Jones!' The Doctor grinned (he always seemed to be doing that) and pushed off what looked like an oddly shaped welder's helmet.

'What are you doing?' Ianto asked. Jack squirmed so he put him down to go trotting off to join Gwen at the computers.

'Well, the circuits were burned out by transforming Jack so I have to fix them. Gwen is working on finding an appropriate source of energy-'

'Can't you just use your TARDIS?' Ianto asked. The Doctor shrugged.

'I would have, but this place is TARDIS-proof. Torchwood stole the technology off UNIT in the 70s and installed it in most of the Torchwood bases in the empire to stop me getting in. The Daleks disabled it remotely from inside Torchwood one because they also needed to be able to get in or out but I guess if Jack had been aware of the protocol he'd have forgotten about it now.'

'Well how do you power your TARDIS then, cause surely both power sources would be compatible?' Ianto asked.

'There is an exploding star in stasis in the engine. It's an infinite power source, if sometimes a little slow.'

'What about the rift energy?' Gwen asked. 'Cause Jack said that you sometimes stop here to refuel.'

'Well that's a secondary power source. It's mostly used to maintain the time lock around the Eye of Harmony and power the coffee machine but... Actually, that might work.' He pointed to Ianto. 'Where's your rift manipulator? Don't think I don't know you've got one! Ever since Jack told me about you all, I've been keeping a close eye on you.'

'It's there, sir,' Ianto pointed and the Doctor ran up the stairs. 'It doesn't work, though. Not very well, anyway.'

'That's cause you didn't have me!' the Doctor grinned and began fiddling with his "screwdriver". Jack leaped out of Ianto's arms and ran towards where the Doctor was working. He sat and watched with attentive eyes. 'Got it!' the Doctor exclaimed triumphantly and bounded back towards the Chameleon Arch in the medi bay, a thick wire lead trailing behind him.

The Doctor stepped back and examined his work. He reached out and picked up the helmet. Ianto tensed, waiting for the Time Lord's body to be seized by electric shocks, but the Doctor appeared uneffected.

'Is it ready?' Ianto asked. The Doctor looked up at him and nodded.

'Okay, Jacky-boy. Jump up here.' The cat landed gracefully on the examination table and flicked his tail under the Doctor's nose. When the cat settled, the Doctor gently placed the helmet over the cat's body.

'Are you sure this is going to work?' Gwen asked anxiously.

'Reasonably,' the Doctor shrugged. He fiddled with the helmet for a few seconds and then stepped back. 'Jack, stay there,' he ordered, then pointed to Ianto, who was still standing next to the rift manipulator. 'Ianto Jones, there is a control circuit over there, can you see it?'

Ianto looked. 'Yes, sir,' he replied and took it in his hands.

'Good. I've had to improvise a bit so the setup isn't that reliable. Is the light green?' Ianto nodded. 'Okay, then,' the Doctor said. Under the helmet, the cat's tail flicked nervously. 'That means the energy source is still stable. Press the button.'

Ianto shared a look with Gwen. She stared back at him. She looked impossibly young with her eyes wide like that. Silently, she nodded. Ianto took a deep breath and did as he was told.

A surge of energy pulsed down the lead with an electric crackle and hit the helmet. Jack the Cat yowled loudly, a sound that made Ianto panic. He reached to switch the thing off, but the Doctor threw out a hand.

'No!' he yelled. 'It's working!'

Ianto looked back at the creature underneath the helmet. Fur was receding over the cat's body as he grew, limbs lengthening and thickening, joints fusing and splitting, becoming human arms and legs. The cat's screaming howls changed voice, becoming more recognisable as Jack's usual american drawl. The helmet fit the head now, and as the cat's back lengthened, he curled in on himself, hands reaching up to grip his head as he screamed.

Then, as abruptly as it had started, it stopped.

Without thinking, Ianto dropped the control circuit and leaped down the stairs to his lover's side. Jack wasn't moving.

The Doctor pulled off the helmet and discarded it, rolling Jack's naked form onto his back.

'Is he going to be okay?' Gwen demanded, making her way down the stairs as fast as she could.

'Trauma like that on an effectively human body,' the Doctor said. 'I think it killed him. There's a reason only Time Lords have this type of technology.'

'Jack?' Ianto murmured.

Jack's eyes flew open. He sucked in a huge gasping breath and grinned.

'Shame,' he said. 'I was having fun.'

'Oh, you bastard,' Gwen giggled. 'We couldn't have you stay as a cat forever.'

Jack shrugged. 'I dunno. The view this morning was something I could get used to.'

Ianto glowered at him. 'You got my duvet covered in cat fur.'

Jack winked and sat up. 'I'll make it up to you,' he promised. 'Doctor!' he exclaimed, turning to the Time Lord who had watched the whole affair with a quizzical smile. 'If I had known all it took was faulty Time Lord technology and a species transformation to get you to come and say hi, I would've tried it ages ago.'

'Oh, you know me, captain,' the Doctor shrugged, but his grin gave him away. 'I'm not really a cat person. Even if they are my friends. Human suits you.'

In the corner of his eye, Ianto saw Gwen make a face like she was about to disagree. He laughed, and Jack twirled around to catch Gwen in the process of rearranging her face into a more acceptable expression.

'What?' Jack demanded. Gwen gave an undignified snorting laugh and shook her head.

'I think she disagrees,' Ianto pointed out mildly. Jack stood up and faced her properly, smoothing out his non-existent collar.

'What are you talking about?' he asked. 'I'm gorgeous.'

'Yeah, okay,' Gwen conceded. 'Just put some pants on.' She handed Jack's clothes, which had been piled in a discarded heap onto the floor, back to him and turned to take her previous position. As she passed Ianto, she muttered, 'He was a cute cat, though.'

'Yeah,' Ianto agreed with a suppressed chuckle. 'He was.'

The End