2. The finger joints are cramped with chalk - The Ballad of Lady Smallwood by A.J. Hall

“Rheumatics, I’m afraid. Plays merry hell with my line dancing. To be honest, it was a relief when Mike called. Gave us an excuse to beat a decent retreat. Sherlock always did play the poor boy like an instrument — of course, the piano’s been beyond me for years, not that I was ever any good. Mike, you see, thinks of rules as things to be circumvented; Sherlock never sees them at all. Tell me, what is this undercover posting really about?”

“I’m sorry, I’m —”

“Bound by the Official Secrets Act. Of course, my dear. So’s Mike. But to get Sherlock to go along with it — No. Different question. What brings you here?”

She reached into her bag. “This.”

The Dynamics of Combustion

“My dear, no-one outside the family’s read that in years. I was twenty-five years ahead of the field and the wrong sex to boot. Way out of date now, of course.”

“Still, you’re a genius in the principles of complex systems. Which is what I need. If I describe a system, can you show me the optimum pressure spots for total disruption?”

“I’ll give it my best shot. Because if someone’s using official nonsense to hurt my baby boy, my actions, I promise, will be ruthless, resolute and bloody.”