"You take that flute out one more time," said Jack, evenly, without looking up from the board, "and I'll take it away and beat you to death with it."

The Doctor's hand stopped halfway to his inside pocket, and he hesitated only briefly before rallying his affronted pride.

"Well, there's really no call for threats," he said, his mouth curving downward and his hangdog expression radiating pathos. "And it's a recorder, Captain. Not a flute. Really now! If this is the thanks I get for helping you to – "

"I had the situation under control," said Jack, finally reaching a decision and nudging his queen's rook two squares to the left, in the lee of which he pinned the Doctor with a pointed stare. "You were interfering."

(Jack howled in pain as the Weevil's yellow canine teeth pierced the heavy fabric of his coat, ripped through his shirt and sank into the meat of his back. Blood welled up at once, soaking his clothes, and he felt it chewing down on him as if he were an overcooked steak. He drove his elbow up and back, but failed to connect...)

"Oh, I'm always interfering," said the Doctor, with a distinct gleam in his eye. "You ought to know that. I don't expect I've changed in my old age."

He left the unspoken query hanging in the air like a piñata, dropped his chin into his palm and promptly lowered his gaze to the chessboard. In the ensuing silence – and mildly grateful that the man's attention was elsewhere for a moment – Jack studied the Doctor. Of course there were photographs of his various incarnations stowed away in a file in Torchwood's records. The file had a whole drawer to itself, in fact. And Jack had displayed a particular interest in this one, who seemed to be the most elusive of all.

(Just as the pain reached intolerable levels, Jack felt the creature's weight shift and it ceased its assault, releasing him from its steel-trap bite and sitting up. It made a curious sound, halfway between a dog-like whine and a soft ululation, and then clambered a little unsteadily to its feet...)

There were only a handful of photos of this incarnation, most of them taken during the Cybermen's abortive attempt to invade the Earth. The photographer, a charming, well-preserved widow by the name of Isobel Turner, had declined to surrender them to UNIT at the time, but Jack's powers of persuasion had always broadcast on an entirely different channel.

"Doctor," he said, lacing his fingers together on the table. "You of all people should know I can't tell you anything about your future."

"I didn't ask, did I?" said the Doctor mildly, not looking up from his careful consideration of a knight. But Jack saw the slightest, tiniest wrinkle creasing the corner of the other man's mouth as he spoke. After a moment's more thought, he evidently decided to abandon the knight for the time being, and reached for a white pawn instead.

(Someone was playing a flute. What the...? Jack struggled up onto all fours, dragging cold, damp night air in and out of his lungs and wincing as the savage bite wound in his trapezius muscle gradually knit itself back together. The blood flow quickly slowed and stopped altogether, although he was still sticky with the stuff, and felt slightly sick as a result. And as his head cleared, he heard the halting strains of 'Three Blind Mice'...)

"No, you didn't," said Jack. "In fact, that was the loudest silence I've ever heard."

"Well, you can't blame me for being curious, now can you? I'm only human."

"No, you're not."

"Figure of speech, Captain," said the Doctor testily, finally setting the pawn down again. "Merely a figure of speech."

(After what felt like three and a half ice ages, he regained enough strength to roll over and sit up, and when he did, the sight that met his eyes apparently blew a minor fuse in his speech centres; all he could do for a few seconds was stutter like a broken record...)

"Your move," the Doctor was saying, that soft voice slicing through Jack's memories like a tiger shark angling across a reef; and, he suspected, with much the same intent. He decided to play to his defence instead.

"Why are you here?" he asked, bluntly. He glanced down only for as long as it took to bring his queen in to capture the tantalisingly exposed pawn. He knew it was a feint on the Doctor's part, but suddenly, Jack wasn't in the mood to concentrate on any game but the one going on above the board.

"I just happened to drop in, that's all," said the Doctor, but he spoke a shade too innocently, and Jack was no innocent.

(The Weevil was sitting on its haunches, head tipped back and swaying ever so slightly on its neck, gazing up at a little man with a mop of tousled black hair, wearing a frayed and oversized morning coat and a wonky bow tie. The man was playing a flute of some kind, and it was this music – a little off key but none the less plangent for it – that had lulled the creature. Jack finally regained control of his tongue and said...)

"Doctor?"

For a moment, the other man didn't contrive to indicate that he'd even heard. One hand strayed out across the chessboard, descended, grasped a bishop and moved it in for the kill. Taking Jack's queen, the Doctor picked it up and twirled it in his fingers, a thoughtful expression prowling across his face. Then he set it down at the side of the board and gave his opponent a warm but very carefully rationed smile across the few remaining black pieces.

"And that," he said, smoothly, "would be checkmate. Thank you for a pleasant game," he went on, putting his hands on the table and rising to his feet, "but I'm afraid I really must be running along now."

"You didn't answer my question," said Jack. He'd remained seated.

"What question?" asked the Doctor, impishly.

"Why are you here?"

"Let's just say I'm covering my tracks, shall we?"

"What?"

"Goodbye, Captain," said the Doctor.

Only once the little man had left the room did Jack's eyes widen considerably as a thought hit him in the back of the head at the speed of shock. Tumbling out of his chair, waving his arms for balance, he raced for his office, dived for the filing cabinet and and yanked open the drawer containing the Doctor's file.

The drawer, now suspiciously light, hit its stops with a dull thud. Jack looked down with a deep sense of resignation.

Then he reached in and picked up a single, solitary Jelly Baby.