When Gwen Cooper walked into the Torchwood Hub at eight am that morning, it was to find Ianto Jones (wearing yesterday's suit) sipping tea at his computer and talking to a black cat.

'Uh... Ianto?' she asked casually as the cog wheel door clanged shut behind her. 'What is that?'

Ianto's head shot up at the sound and he spied her staring at him wide eyed and eyebrows raised.

'It's a... Uh, it's a cat,' he replied stupidly.

'Yes, I can see it's a cat,' Gwen replied. 'I'm wondering why it is helping you do your work.'

Ianto glanced back at the cat to see it walking onto his keyboard and settling itself on the keys.

'No, Jack!' Ianto hissed and Gwen snorted. 'Don't sit there!' Ianto unceremoniously plucked the cat from its perch, despite its cry of protest, and placed it on the ground. 'You're supposed to be helping me!' He complained. The cat just meowed piteously and trotted happily over to Gwen, who cooed and crouched to meet it.

'My, aren't you a pretty boy?' she crooned, picking it up and holding it in her arms as she approached Ianto's desk. 'You named the cat "Jack"?' she asked with a smirk. 'What, is one not enough?'

'Actually, Jack chose his name,' he replied, supposing that technically it wasn't a lie.

'As if his ego couldn't get any bigger,' Gwen sighed. The cat hissed and squirmed out of her arms, turning and leaping back onto Ianto's desk.

'I don't think he likes being insulted,' Ianto pointed out, absentmindedly stroking the cat's ears.

'I was talking about the human Jack not the cat,' Gwen replied and Ianto shrugged. 'Where is he, anyway?' Ianto tilted his head in the cat's direction. 'No seriously,' Gwen said. 'Where is Jack?' Ianto pointed at the cat. The cat just rubbed his head affectionately against his hand. 'Ianto, please, be serious. Where is Captain Jack Harkness? You know, our boss?'

'Sir!' Ianto called. 'Where are you? Gwen wants to see you.'

The cat meowed and blinked it's blue eyes at Gwen.

There was a moment of dead silence, then Gwen's eyes began to widen again.

'No,' she said incredulously. 'No way.'

'I'm afraid so,' Ianto sighed, rubbing his forehead.

'How?' she asked. Ianto pointed to the examination table a way away where a strange looking helmet sat glinting under the fluorescent lights.

'He touched that,' Ianto explained. 'It came through the rift this morning.'

'When?' Gwen demanded, feeling a little insulted they had gone to get it without her.

'Around Four am.'

'Right, well,' Gwen said, nodding her head. 'We should probably think about trying to reverse it. Uh... what is it?'

Ianto sighed and shrugged his shoulders. 'I have no idea.'

'Its a Chameleon Arch,' a new voice announced over the Comms. Startled, Gwen and Ianto both looked around for the source. The cat - or, rather, Jack - sat up straight and began to purr. ''Ello, Torchwood,' the voice - a man's voice - and one they'd both heard before, said. 'Remember me? We saved the universe together. What you have there is a faulty Chameleon Arch and I'd really prefer if I could have it back.'

'Doctor!' Ianto called.

'Jack's Doctor?' Gwen repeated. The cog door rolled open.

'That's me,' a grinning man in a brown pinstripe suit and a trench coat announced, gazing around the place. 'And I tell you, for a top secret government facility dedicated to keeping Earth safe from aliens, you really need to do a better job at keeping us out.'

Jack leaped off Ianto's desk and ran towards the newcomer, meowing loudly and purring at the same time.

'Hello, Jack,' the Doctor greeted his old friend and picked him up. 'So you're a cat now, hmmm? Funny, I never thought you are a cat person.' Jack the Cat rubbed his head against the Doctor's chin. 'Yes, I suppose you are an everything person.'

'This- this Chameleon Arch thing,' Gwen stammered. 'Is it yours?'

'Jack said it was Time Lord technology,' Ianto added. 'Although he also said it was safe, so obviously he's not right all the time.'

'Yes, it is Time Lord technology,' the Doctor agreed. 'But no, it's not mine. I followed it here after I registered a TARDIS explosion. Found the wreckage, but the blast sent bits flying throughout time and space.' The Doctor whirled about (still holding Jack) until he spotted the object in question and ran down the stairs to what had been the medical area before Torchwood lost its medic. As he went, he pulled something out of his pocket. It looked like a sort of silver and blue probe and made an irritating buzzing noise.

'You, in the suit-' the Doctor called. 'How did you get it here?'

'Wrapped in Jack's clothes,' Ianto replied. 'Didn't really fancy being turned into a cat and Jack didn't need them at the time.'

'I see,' the Doctor said, circling the device and scanning it with his probe. 'Screwdriver!' The Doctor called to Gwen with a certain element of relish in his voice.

'I beg your pardon?' Gwen frowned.

'It's not a probe, it's a sonic screwdriver!'

'I wasn't calling it a probe-' Gwen protested.

'Yeah, you were,' the Doctor said.

'Okay, but not out loud,' Gwen admitted quietly.

'Don't touch it, Jack!' The Doctor yelled, swatting at one of the cat's black paws which looked like it was going to bat at the helmet.

Ianto rolled his eyes and got up from his desk. 'I'll get him,' he sighed and descended to stairs to pick up the cat. Jack snuggled happily into his arms and purred.

'Well that explains a lot,' the Doctor grinned.

'What?' Ianto asked, glancing nervously from the cuddly ball of fur in his arms to the Doctor who was staring triumphantly at his sonic screwdriver. At Ianto's question, he looked up at the scene before him, shook his head at the cat's behaviour and jumped into a very long rapid fire speech.

'This Chameleon Arch is so badly damaged, I'm surprised it's working. The TARDIS it had belonged to had been used by a group of renegades - space pirates, if you will - and they had set up the arch and the TARDIS to work together to determine the dominant species on each planet they landed on. It made it easier to blend in and steal things, apparently. Anyway, because the arch by itself didn't quite have the computing power to determine the dominant species of Earth when it arrived, one wrong calculation and instead of a dolphin, the next person to use it is turned into a cat. Probably a good thing, considering the circumstances. Anyway, the circuit was misfiring because of the blast and the genetic transformation matrix was surging with excess energy. The fact that Jack got turned into anything at all is testament to how badly damaged this arch is. He just happened to be the first living thing it touched. At least it was him and not anyone else. I'm not sure they would've survived.'

'Can you fix it?' Gwen asked.

'Can you turn him back?' Ianto questioned.

'Oh, probably,' the Doctor answered. 'Gwen Cooper!'

'Yeah?'

'Hello. Would you pass me that chocolate wrapper by your foot?' Gwen began ferreting around on the floor.

'Uh, what are you doing?' Ianto asked.

'I'm fixing it,' the Doctor answered, fiddling with the foil Gwen had just handed him.

'Right,' Ianto muttered.

'Ianto,' Gwen said softly. 'Hey, Ianto? How long have you been awake?'

'Uh, not sure,' Ianto admitted.

'How about you go home?' Gwen suggested. 'You look dead.'

'But-' Ianto began, but Gwen interrupted.

'Go,' she said. 'If we need you, we'll call. Hell, I don't think I'm needed either- this is beyond me. Go home. Get some sleep. Come back later.'

Ianto nodded and began to walk back up the stairs.

'Oh, and Ianto?' The Doctor asked when he was halfway up.

'Yes sir?'

'Take the cat, will you? He's going to be a nuisance.'

The cat hissed at the Doctor and flicked his tail.

'Yes sir,' Ianto agreed and left.