Gwen could only stare at him. "I did what?" she finally eeked out, looking completely bemused.

The Doctor didn't answer as he rushed over to grab the sonic screwdriver she had just discarded, starting to scan the broken object. He addressed Jack as he worked:

"Captain – do you remember a little doo-hicky we once ran across known as a tribophysical waveform macro-kinetic extrapolator?"

"Oh yeah –" Jack nodded, remembering the pan-dimensional surfboard stolen by Margaret Blaine, a Slitheen in disguise.

The Doctor went on: " – well, you see, the one we stumbled upon apparently had a brother… well not so much a brother as an evil twin, I should think. The extrapolator's other half has power capable of blowing up an entire planet – kaboom! – in order to feed the energy to its twin… now do you see why I call it evil?"

"Are you saying that that disk could blow up the whole world?" Rory backed away, wide-eyed.

"Don't be so ridiculous, Rory! – Well, yes it could, but not anymore… now it's been disconnected. Thanks to Miss Cooper, here," The Doctor beamed over at Gwen, who smiled weakly back.

"So… are you saying we have this 'extrapolator' or whatever, with us?" Amy frowned.

"No, not anymore, unfortunately – it was destroyed when my TARDIS crashed in your backyard all those years ago, Amelia. But I think, after she repaired herself, the TARDIS still held some data imprints, some memories, if you will, about the original extrapolator. She must have sensed some of the extrapolator's energy field around this object Torchwood recovered, and thought she was about to get her old friend back…" The Doctor smiled fondly. "Bless her."

"So, wait… the TARDIS crashes us to Earth just so it can find this piece of junk?" Amy scrunched her nose at the broken and sooty device clutched in the Doctor's hand.

"You humans have the phrase 'Bend the heavens'… well, the TARDIS literally can." The Doctor grinned again, obviously impressed with his spaceship's ingenuity.

"That's insane," Rory shook his head, staring at the hunk of metal. "Insane…"

"Not insane, Rory – just extremely very unlikely… perhaps with a dash of improbability," the Doctor shook his head reprovingly at his companion. "Even an irreducibly complex piece of Time Lord technology can get lonely and, well…" the Doctor allowed a small smile to cross his features, "My TARDIS… she needs to be entertained."

The Doctor's eyes started to drift off into space, his mind obviously straying to the blue phonebox parked outside.

"Are you seriously having fantasies about your spaceship? 'Cause even I have to ask you to keep it in your pants, mister," Jack interjected firmly, causing the Doctor to snap into focus again.

"What? No, I wasn't – shut up," The Doctor blinked, straightening his bowtie and turning bright red.

"He calls her 'Sexy'," Amy informed everyone, grinning wickedly at the Doctor's discomfort. Gwen snorted with laughter, while Jack and Ianto had to bite back grins.

"Careful, Pond – remember, I'm not afraid to bite you," The Doctor threatened, baring his teeth at her. However, it only looked like he had a bad overbite, which made Amy giggle.

"Oh please – I'm so scared," She rolled her eyes sarcastically, though she moved to stand over by Rory anyway.

"Biting your companions, now, are you Doctor? Bit kinky, don't you think?" Jack smirked, his arms crossed in front of his chest.

"No, not kinky…" The Doctor defended, looking disconcerted again. "I bite because sometimes that's the only way she'll listen to me…"

"What?" Rory cast a horrified look over at the Doctor, who blinked bemusedly.

"Er…"

Amy, spotting danger, quickly spoke in a loud voice: "Well, it's been a time and a half, but I think it's about time we got back to the TARDIS, don't you think, Doctor? I'm beat!"

"Yes!" the Doctor whipped around to face her, looking extremely thankful. "Yes, I believe our time here is done as well, Amy! The extrapolator's twin is destroyed and… and everything in the TARDIS should have recalibrated by now, I believe… Yes, I think we should be going now."

The Doctor turned to face the Torchwood team again. Gwen looked confused, while Ianto's eyebrows were raised in polite indifference. Jack slowly uncrossed his arms as he locked eyes with the Doctor. Unlike the other two, his expression was slightly dejected.

"You're leaving?" he frowned. Everyone quieted, glancing between Jack and the Doctor.

"Jack…" The Doctor walked toward the captain and clapped a hand on his shoulder. They looked at each other and, after a moment, smiles spread across both men's faces. After another moment, Jack gave a small, involuntary laugh. Both men: both impossibly old and both having seen the unimaginable – bound together with fates neither of them wanted. But all they could do about it at this very moment was smile and laugh and embrace once more.

"Oh, Captain Jack…" the Doctor grinned, gripping the taller man's back tightly before moving away. He looked him right in the eye: "… I'm going to miss you, my old friend."

"Likewise," Jack smiled, his eyes rather red and glistening. Giving a hearty sniff, he distracted himself by putting an arm around Ianto, who was standing right beside him. Ianto blinked and very nearly smiled at this gesture.

The Doctor grinned.

~/~

Jack stood outside, his two employees standing on either side of him. The wind whipped their hair back; Jack's trench coat sailed out behind him. Like a sentry, the three people stood and watched the blue box before them begin to fade away with a strange grinding noise. In a matter of seconds, it was gone.

"So that was your Doctor," Gwen said quietly, still gazing at the point where the phonebox disappeared.

"Was. Is…. And will be." Jack muttered, not taking his eyes from the point either. Both Ianto and Gwen looked at him.

"D'you think you'll ever see him again?" Ianto inquired of his boss, who gave a watery chuckle. Jack stared at the point for one more moment before turning back toward the entrance of the hub.

"That," he said, heaving a big sigh, "is practically inevitable."

Gwen and Ianto followed their boss back inside, unable to hide their confusion.

The End

A/N: So that's it! Did you like it? Did you not? Let me know!

Reviews are love:)