A/N: You know those rules the Doctor harps on about? I'm making up some of my own. I own nothing and the lyrics are from 'Maybe This Time' – Cabaret. Enjoy.

Rule #37. A strong melody makes for a stronger song.

He finds himself in a dusty underground club that is as much World War II as it is the 4050s. There are posters that are fading and peeling and a brass band softly soothing a mellow audience, but space-age gadgets behind the bar and a distinct smell of stale transmit beams. Just as he's gazing upon the oddity that is the view in front of him, he hears a voice.

A voice that's both powerful and unpretentious hitting every corner in the room and for a second, he swears he's heard it before. He's sure he can't have (he checks his timey-wimey watch just to make sure – nope, never been here before) but its melodic qualities resonate deep within him. Frowning, he makes his way through the crowd, carefully trying not to disturb anyone but doing so unintentionally. He makes a beeline for the stage which is engulfed in smoke and he's not sure upon first glance whether it's a half-functioning machine or just the number of cigars in the room. As the voice belts out another verse, louder the closer he gets, he decides the smoke is less important and marches forward, spilling a drink on a well dressed gentleman who curses in a language even he can't interpret (drunken slur. So much harder to understand than Jiggery Pokery.)

"It's gonna happen, happen sometime." The voice gets louder and clearer and he just knows he's heard it before. "Maybe this time - Maybe this time I'll wi-i-i-i-i-n."

The vocals close to a roused and fully appreciative audience who provide whoop and holler so loudly he brings his hands to ears, pouting just slightly as he cranes his neck up to the stage.

Bingo.

"I didn't know you could sing," he comments offhand as he inspects her dressing room (well she says it's her dressing room but he's already spotted the name above the door and Lucinda Everett is not even close to River Song.)

"You never asked," she replies pointedly, applying a thick line of lipstick to her lower lip. She eyes him through the mirror as he struggles to find a place to perch, resolving just to stay standing. "What did you think?" she smirks as she places a chaste kiss against the mirror, leaving a large red print against the reflective surface.

"You brought the house down," the Doctor certifies and River laughs because yes, she did. Thankfully not literally (though ironically if she had, it would have fitted in perfectly with the WWII theme.) His eyes latch onto the brilliantly green dress she's wearing that puddles at the floor and nips in at the waist. Sometime he thinks it's a godsend she wasn't raised by Amy (because it would be all coloured tights and baggy jumpers and this – this is so much better.)

"Cigar sweetie?" She offers him one from a silver case and he marvels at it before scolding himself and then scolding River just as hard.

"Smoking's bad for you." he puts on his best authoritative voice but it falls on deaf ears. He might be the husband but River wears the trousers.

"So is everything, according to you." She raises an eyebrow, expecting a retort but nothing comes so she changes the subject. "How did you get here anyway?"

"I was.." he begins but trails off, forgetting exactly how he did end up here.

"You're on your own again, aren't you?" For a second the games are gone and she asks him genuinely because she knows (more than most) what can happen when he's alone for too long.

"Not exactly," he smiles but it never reaches his eyes. "I'm doing house calls."

A small hmm from River tells him that she's not falling for his lies but he puffs out his chest and crosses his arms over his ribs. "Why are you here?"

Tit for tat. "I'm helping a friend," River returns to her mirror and finishes applying the last touches of make up to her face. He wants to tell her she really doesn't need it but he's spied a few spare make up brushes in the corner and he can already imagine how the conversation would go if he told her out loud (and whatever way he imagines it, he always ends up with make up on his face.)

"A friend?"

"Don't get jealous, darling. A cellmate if you'd prefer."

"River?" There's a tone of warning in his voice but she ignores it. She always does.

"It's not what you think. Not that it's really any business of yours." Her mouth curls into a slick smile as the Doctor scoffs.

"I think you'll find that it is, wife." The word sounds funny off his tongue but it brings a cheeky sort of smile to his lips.

"You call that a wedding?! I don't think so, mister." In the distance a bell rings, telling her she's got 5 minutes left and her eyes sparkle into life. "Show time."

And with that, she's gone. Into the smoke and out on to the stage. He never finds out what the favour or who the friend was, not at this meeting anyway. But it does inspire him to take an added trip to meet Liza Minnelli and though he'll never tell either of the women, River Song sang it better.