When your legs don't work like they used to before.

"Sherlock, come dance with me." Madeline said, holding her hands out to him with a wide smile on her face.

And I can't sweep you off of your feet.

Sherlock threw her an annoyed glance over the samples he was fermenting. "And why would I do that?" He asked, "I'm working."

Will your mouth still remember the taste of my love.

Madeline frowned at him. "Yeah, but I saw a really cool music video. Please will you dance with me?" She pleaded. Sherlock rolled his eyes.

Will your eyes still smile from your cheeks?

"You and I can't dance. I thought that's already been firmly established." He pointed out.

And Darling I, will be loving you till we're seventy.

"Please?"

And Baby, my heart could still fall as hard at 23.

Sherlock rolled his eyes and made sure to turn the flame on his Bunsen burner down before conceding. Madeline gave a little squeal of excitement and rushed to turn on the song on the laptop.

And I'm thinking about how- people fall in love in mysterious ways.

The music was soft, and Sherlock was vaguely certain he knew who the artist was. Madeline stepped up to him and held up her hand.

Maybe just the touch of a hand.

Sherlock fought the urge to roll his eyes and indulged her, intertwining his fingers with hers and placing his other hand on her hip.

Well, me- I fall in love with you every single day. And I just wanna tell you I am.

"And now we sway." Madeline murmured, more to herself than to Sherlock. She seemed to be counting the beats of the song as if she was waiting for something. He kept quiet and let her orchestrate the tempo of their dance.

So honey now,

She spun suddenly, taking Sherlock with her. He'd fallen into almost a trance from the lack of real movement, and it took a lot of clumsy effort on the detective's part to keep from trodding on Madeline's feet.

Take me into your loving arms.

"Sorry," She said when he opened his mouth to complain. They kept actually moving, stepping around the den of 221B in partial rhythm with the song.

Kiss me under the light of a thousand stars.

Sherlock noticed Madeline's mouth moving only slightly as she resumed counting the beats of the song. It grew a little louder, but the tempo was still pleasantly slow.

Place your head on my beating heart.

"Are you going to dance with me or will we continue to stumble about?" Sherlock demanded.

I'm thinking out loud.

Madeline immediately snapped to attention.

Maybe we found love right where we are.

"No, I mean yeah we'll dance. No to the stumbling. We're actually dancing, now." She reminded him. Sherlock kept his eyes from reaching for the ceiling with obvious effort and decided to spin Madeline.

When my hair's all gone and my memory fades.

Her hand on his shoulder tightened momentarily and then relaxed as she gave up trying to orchestrate the dance and let Sherlock try to waltz them around the flat.

And the crowds don't remember my name.

He stepped on her feet more than once, and a couple of times he banged his knee on the table in an effort to keep himself in balance with Madeline.

When my hands don't play the strings the same way.

He swung Madeline around suddenly when he saw that he was about to waltz her right over his violin that he'd left on the floor beside his chair.

I know you will still love me the same.

Madeline laughed and looked him right in the eyes, an act she'd been growing increasingly more comfortable doing.

'Cause baby your soul could never grow old, it's evergreen.

Sherlock made a small note to himself that her pupils were dilated, and a small smile was curling the corner of her mouth in a way that he found fascinating.

And baby your smile's forever in my mind and memory.

Madeline felt herself grow even giddier as the song grew close to her favorite part.

I'm thinking 'bout how, people fall in love in mysterious ways.

She allowed herself to lean a little bit closer to Sherlock, and was secretly pleased when he let her.

Maybe it's all part of a plan.

She looked up at him again, and he gave her a rare smile.

Well I'll just keep on making the same mistakes.

She'd distracted him, and he paid the price by knocking his hip painfully on the metal frame of John's chair as they passed it.

Hoping that you'll understand.

"Are you okay?" Madeline asked, trying to sound sincere under a bubbling laugh. He cut his eyes to her. "I'm fine," He snapped.

That baby now…

Madeline's eyes widened. "This is my favorite part!" She squealed. "I need you to pick me up and spin me!" That took Sherlock aback.

Take me into your loving arms.

"Why?" He asked.

Kiss me under the light of a thousand stars.

"Sherlock Holmes, spin me around or I'll move your Petri dishes in the pantry." Madeline demanded.

Place your head on my beating heart.

Sherlock quickly looped his arms around Madeline's waist and hoisted her up with a little bit of effort. She balanced herself by bracing her hands on his shoulders and grinned down at him.

Thinking out loud.

Sherlock concentrated on not running her head into the ceiling fan.

Maybe we found love right where we are.

He was so focused that he didn't realize the coffee table was right behind him, so when he bumped into it he completely let go of Madeline as he fell.

So baby, now.

Her hands on his shoulders instinctively latched onto his shirt, turning the detective awkwardly. Luckily Sherlock was in a direct line with the couch, so when Madeline fell she landed on the cushions on her back.

Take me into your loving arms.

Unfortunately Sherlock came down after her; and he landed on her stomach with quite a bit of force, even though he tried to angle himself away.

Kiss me under the light of a thousand stars.

Madeline caught her breath, wheezing a little bit. "You're so damn bony," She told Sherlock. "I think you broke one of my ribs."

Oh darling, place your head on my beating heart.

"You'll be fine," Sherlock told her, repositioning himself so that he was braced above her in a truly awkward fashion.

I'm thinking out loud.

"I made sure to fall in a way that wouldn't hurt you." He explained smugly, noting that Madeline's pupils were still dilated so she couldn't have been in severe pain.

But maybe we found love right where we are.

Madeline leaned up and kissed the detective on the mouth. He was a bit startled- he'd intended to be the one to start the kiss- but it was welcome all the same.

Oh baby we found love right where we are.

Sherlock leaned down and kissed her back, and he could feel Madeline smile underneath his lips as the song drew to a close.

And we found love right where we are.