A Very Sherlock Musical

So, you know how musicals are set in a world where people just burst into song every five minutes, and everyone around them automatically knows to join in with the tune and choreography? This fic is set in that world.

John finds it extremely frustrating that Sherlock won't sing their theme song with him.

Not Season 3-compliant.

Thanks to Sapph, Earlgreytea68 and Passeriform for betaing/lyric help (any appalling bad lyrics remain my fault), and Ariane DeVere for her very useful episode transcripts.

“And you invaded Afghanistan,” said Sherlock, his voice still choked with laughter.

“Not alone,” managed John through his own giggles. Music started to swell and he felt a surge of joy. He hadn't been part of a duet for ages, and never after knowing his partner for so little time. The opening bars made it clear that this was going to be the best kind of duet as well, the 'we're in this together' kind of song that made you feel as if the two of you could take on the world and win. He met Sherlock's eyes, opening his mouth to let the first line come out and-

“Sherlock, what have you done?”

The music cut off abruptly, but not before John had seen the look on Sherlock's face. All his amusement had wiped away with the start of the music and been replaced with a look of total panic. When Mrs. Hudson interrupted, relief was his first reaction, although he quickly focused on her and her worry instead.

John frowned as he followed Sherlock up the stairs. Why would he be panicked by a duet? It was a