For the flash fic fest on tumblr, anonymous asked for mythea with the title: swindlers with strength. Rated T for mention of prophylactics.
"Well, you can't fault their, erm, energy?" Anthea ventured after a few minutes.
Mycroft was still staring aghast at defiled desk in his private study. The one no one - not even his obnoxious brat of a baby brother - was supposed to be able to breach. Technically it was a panic room, but had seemed the most suitable option when he'd had his house designed and built. He'd even gone so far to ensure that the plans on record were falsified so the room didn't show. So how on earth…
"Sherlock," he muttered after a minute. "It has to be. No one else would have the desire, the need, the perseverance…"
"The strength?"
There was a definite hint of laughter behind her words. He wanted to glower at her, he really did, but when she tucked her arm through his and laid her head on his shoulder, all he could do was kiss the top of her head. "Strength or no strength, he swindled me out of my peace of mind," he muttered. "Which means it's time for me to do the same to him."
Anthea straightened up and looked at him in alarm. "You don't mean…"
His grin was positively evil as he replied, "Oh yes, time to bring in the big guns." He straightened his tie and sat behind his condom-bedecked desk. "Anthea, my darling, please ring Molly Hooper for me."