AUTHOR'S NOTE: This was written for we-are-torchwood's week-long The Empty Child/The Doctor Dances Anniversary Celebration. It was supposed to be one prompt per day, but as I was really busy, I had to condense three days into one effort in order to participate. (I hit Thursday and Sunday pretty solidly, but Friday is more of a drive-by. Oh, well.)

Prompts:

Thursday: Glenn Miller music

Friday: Jack gets nostalgic and tries to incorporate elements of the 1940s into his everyday life in the 21st century

Sunday: dancing

In The Mood

Gwen stared up at the banner. "Party like it's 1947?" she read, then turned to stare at Jack. "This is why you told us to dress 'classy'?"

Jack spun around, flinging out his arms to encompass the interior of the posh nightclub they had just entered. "It's the sixtieth anniversary of the rebuilding of the Seashell Club!" he announced. "It's a theme party!"

"A nineteen-forties theme party?" Gwen glanced around at the clientele. A few were dressed in modern style, but the majority wore vintage fashions and sported victory rolls or even pencil mustaches. "You didn't tell us we had to come in costume."

"You don't. You're fine as you are." Jack turned to admire a passing couple. The man was dressed in a wide-shouldered pinstripe suit, and Jack grinned. "See? Ianto will fit right in here."

Ianto rolled his eyes, but said nothing.

Jack beckoned and led his group toward the maitre d'hotel's stand. "Look, I told you I owed you all a nice dinner, and the steaks here are the best in town. The theme is just the icing on the cake. They even got a live orchestra in for the anniversary. Music, dancing, good food, a full bar selection… what's not to like?"

Owen began a list under his breath of what he didn't like, and Gwen appealed to Toshiko with her eyes.

"I think it's kind of nice," Toshiko said, smiling at Jack.

"Fine," Gwen sighed, smoothing her dress slacks self-consciously. "As long as the food is good, I suppose I can pretend Halloween came early this year."

Dinner was excellent, as Jack had promised. During the meal he recited the history of club, which had sustained heavy bomb damage during the war, and had taken years afterward to rebuild and reopen. A more recent renovation had restored the club's original art deco interior, which was currently festooned with streamers and balloons. Colorful ticker tape dangled from the balcony railing, and vintage bills advertising famous singers and band leaders of a bygone age decorated the walls.

Jack, timeless and ageless, fit right in. Knowing about the theme in advance, he had dressed for the occasion: His normally-spiky hair was slicked back with some kind of product that made it appear darker and gave it a patent-leather gloss, and he'd shed his greatcoat at the coat check to reveal a full RAF officer's dress uniform. It was in excellent condition, and too perfectly tailored to be a costume replica. More than one head turned to admire the well-cut, classic figure as he passed by.

Gwen waited until Jack slipped away to put in a request at the bandstand before she leaned across the table. "So what do you make of Jack's getup?" she asked her teammates.

Owen snorted into his glass. He had been taking full advantage of the bar all evening, knowing Jack was picking up the tab. "I've always maintained that period military—"

"I don't mean that," Gwen cut him off. "Look, we all know Jack has an affinity for World War Two-era clothes, right? But we've never asked why. Out of all the centuries he's lived in, all the planets he's been to, why would he choose to identify himself with Britain in the nineteen-forties? Why not, I don't know, Mars in the thirtieth century?"

"I doubt Martian fashions would fit in well in Cardiff." Owen finished his third cocktail and gestured to a waiter for a fourth. "Though he'd probably look no less straight…"

Gwen ignored his remark and pointed across the dance floor, to where Jack was speaking with a waitress. Or flirting, to judge from her body language—though that tended to be the natural byproduct of meeting Jack, especially enhanced by the striking costume. "Look. That uniform is perfectly preserved. He's gone to a great deal of effort to keep it pristine. It's like he wants to keep living in the forties."

"Well, he lived through the entire twentieth century," Toshiko put in. "Maybe hanging on to things from his past is a way to remember. You know, his version of a photo album."

"But it seems to only be the forties he's concerned with. Why not the twenties, or the seventies?"

Ianto, who had been doing his best to ignore her, cringed. "Have you seen seventies fashion, Gwen?"

Gwen turned to him. "Ianto, you know Jack's wardrobe better than anyone. Do you know if he saved clothes from any other era?"

Ianto rolled his eyes. "Is this really important?"

"I think it is!" She leaned forward. "I think there's something significant about that decade. Something important to Jack." She turned to Toshiko. "Tosh, when you and Jack went back to 1941, did he…"

"Gwen." Ianto's voice was firm. "Leave it."

Gwen opened her mouth to retort, then narrowed her eyes at him. "Wait. You know something, don't you?"

"I know a lot of things. I know for a fact that Jack doesn't like other people digging into his past."

"Well, sometimes we have to dig, when he keeps so much from us."

"Don't you think he has a right?" Ianto shook his head. "It's his life, Gwen. His memories. If he wants to keep that to himself, we've no right to invade his privacy."

"I'm not trying to invade anything. I'm trying to understand him. I thought you of all people would be sympathetic to that, Ianto." She crossed her arms in challenge, bolstered by the drinks she'd consumed with dinner, and squelched the internal voice of warning. "Or maybe you're not as close to Jack as you lead everyone to believe."

Owen slapped his hands on the table with an astounding lack of coordination. "Boom. 'S gotcher number, teaboy."

Ianto gave them both a look of disbelief and turned deliberately away. "I'm not even going to validate that with a response."

"I don't think it's fair to take it out on Ianto," Toshiko put in, glaring at Owen, "and I see his point. But I also think Gwen's right. When I was sent back in time with Jack, when he saw where—when—we were, for a moment he looked so happy to be there. His whole face just lit up."

"I knew it!" Gwen leaned forward again. "There must be something special about that time. Do you think it was the war? The thrill of soaring into battle?"

"Soaring?" echoed Owen.

She nodded toward Jack. "That uniform's Royal Air Force, isn't it? Think of the adventures he must have had…"

"It wasn't the war," Ianto cut in before she could wax too enthusiastic. "Jack once said that battle is something you survive, not something you live for."

"Well, what could have been so special, then?" Gwen pressed.

"The boys in uniform?" Toshiko suggested, eyes following a passing group of costumed sailors.

"Certainly wasn't the food," Owen contributed, halfway through another drink. "All that…" He paused to hiccup. "…rationing."

Ianto sighed deeply. "You aren't going to let this alone, are you?" He gazed in Jack's direction, his expression inscrutable. "You're right, at least in part. Something happened in 1941, something that changed his life. He likes to remember what that meant to him. But it's not my story to tell, so don't ask me for any more than that."

"You…" Gwen frowned. "But how do you know? How did you find out about Jack's past, Mr. Respecter-of-Privacy?"

"Because he told me." Ianto shot her a dark look, then turned it on Owen. "Because despite what some of you seem to think, we actually do spend time together outside the bedroom. Sometimes we talk, like normal… whatever we are."

The table fell silent. Toshiko stirred her drink. Ianto's gaze drifted back to the dance floor, where he watched the swaying couples with a faraway look.

Several minutes passed before Toshiko cleared her throat. "The music is nice," she observed.

Ianto nodded. "'A String of Pearls,'" he answered absently.

"Is that the title of the piece?" Ianto nodded, and Toshiko smiled. "You really do know everything, don't you?"

Ianto shrugged. "Jack's a Glenn Miller fan. He had this tune on an old shellac record that had been broken and glued back together. It skipped in the same spot every time he played it, so I finally bought him the whole big band collection on CD."

"That was sweet of you."

One corner of Ianto's mouth quirked up. "It was purely selfish. Have you ever listened to a skipping record?"

Gwen crossed her arms, feeling petulant. "If Jack's such a big fan, I don't suppose Glenn Miller has anything to do with this big life-altering secret you're keeping?"

Ianto favored her with another eye roll. "Gwen, if Jack wants to share what happened, he'll tell you himself, when and how he chooses."

"Knowing Jack, he probably shagged Glenn Miller," Owen put in loudly, earning glares from those at his own table and several neighboring ones. He tossed back the rest of his drink and clapped the empty glass on the table.

"No," Ianto said quietly. "They only met once, and it was just a few hours before he died."

That got his teammates' attention—even Owen's, unfocused though it was. "What happened?" asked Gwen.

"Jack tried to…" Ianto glanced around and lowered his voice. "Jack wanted to save him. He knew Miller's plane had disappeared over the English Channel during the war, so he posed as an American pilot and volunteered for the flight."

Owen scowled. "I thought you weren't supposed to change history. Rules, and everything."

Toshiko glanced from him to Ianto. "I'm guessing he didn't succeed. Did he?"

Ianto shook his head. "There was a bad storm. Nothing he could do." He looked back across the dance floor, where Jack was now speaking with the band leader. "Everyone on the plane died."

Gwen bit her lip. "That wasn't… the thing you mentioned before, the one that changed him…?"

"No. Different year. 1944." Ianto sat back, twirling the stem of his own wine glass between his fingers. "Just another death."

They lapsed into silence again, but a moment later were roused by the sound of an iconic horn melody. Jack hurried gleefully back to the table just as the first bars of "In The Mood" drew the next wave of enthusiastic dancers from their seats.

"Time to dance!" Jack announced as he reached them, shucking his uniform jacket and tossing it over the back of his chair. Beneath, he wore the familiar blue shirt and braces, though a black necktie dressed up his usual ensemble. "Who's up for some swing? Ianto?"

Ianto's eyes widened, and for an instant it seemed he would accept Jack's offered hand, but then he drew back and shook his head. "Sorry, I… I can't swing dance."

"Sure you can! Nobody's watching; they're all too busy dancing." Jack nodded back toward the floor, which was rapidly filling.

Ianto shook his head again. "I don't know how. Why not ask one of the girls?"

"Gwen? Tosh?" Jack held out his hand to each in turn, but they both declined with expressive head-shakes. "C'mon, you can't not dance to Glenn Miller! This is classic!"

"What about her?" Owen pointed to a nearby table, where a young woman in a flared skirt and seamed stockings was tugging valiantly at her companion's arm, trying to get him up out of his seat. Jack took a few steps and spoke to her, and a moment later they were headed for the floor, hand-in-hand, wide grins splitting their faces.

Jack was magnificent on the dance floor. Every movement was grace blended with strength as he twirled and lifted his partner to the music. Jack expertly led her through a few step sequences, then some simple lifts, which she executed with the easy carelessness of long practice. Trust established, they were soon demonstrating an impressive assortment of complex swing moves and aerials. As their routine became more dynamic, the other dancers moved away to give them more space, and a spotlight shone down from the balcony to highlight their performance. When the song finally ended, the patrons clapped so long and insistently that Jack and his partner were obliged to take their bows before they could leave the dance floor.

Jack gallantly escorted the young lady back to her own table, then returned to his seat, exhilarated and laughing. He drained a water glass and fanned his face with the wine menu. "I should make that part of the mandatory Torchwood training regimen," he grinned. "What a workout."

Ianto raised an eyebrow. "It's certainly an impressive skill, but I'm not sure how much use fancy footwork would be against hostile aliens."

Jack captured his hand and leaned close to whisper something in his ear. The only word Gwen caught was "workout," and when Ianto's ears flushed, she decided she didn't need to know the rest.

"Where did you learn to dance like that, Jack?" she asked instead, hoping that he might reveal more of his own history while immersed in historical surroundings.

Jack shrugged. "Had to, living here during the last couple of centuries. Everyone used to dance. Up until the last few decades, dancing was an expected social skill. You took someone out to dinner, you danced with them. You went to a wedding, you danced. You went to a club, you danced. Even the military had formal balls. And it was real dancing, with actual steps, not that random discotheque grinding all the kids do nowadays."

"You sound like an old man, Jack," laughed Toshiko.

"Well, I am an old man." Jack winked. "And I like my old-style dancing. Balboa, Lindy hop, quickstep, even the occasional waltz can be nice. And there's nothing more romantic than a nice slow fox trot." He looked up as the band began another song. "Speaking of which, here's my second request."

Ianto listened for a moment. "'Moonlight Serenade'?"

Jack stood and pulled him to his feet by the hand he still held. "Yep. I had a feeling you would turn me down for swing. Come on."

Ianto balked. "But Jack, I don't know how…"

"I'll lead. Just trust me and follow." He smiled, and a significant look passed between them. "Like you always do."

They moved to the dance floor, where Jack guided Ianto smoothly through a series of steps that fit the gentle sway of the melody perfectly—slow, slow, quick quick—and soon they merged into the sea of couples moving across the floor.

Toshiko accepted an offer to dance from a handsome sailor, and Owen staggered off in search of the loo, leaving Gwen alone at the table. She half-closed her eyes and let the music flow over her as she watched Jack and Ianto circling the room, oblivious to the crowd.

In that moment, surrounded by the smooth strains of Glenn Miller, the swirling dancers, the soft light, the swish of skirts and uniforms, all of the secrets and mysteries ceased to matter. Jack was smiling, Ianto more relaxed in his arms than she had ever seen him, and the music was beautiful.

That, she realized, was all she really needed to understand.