Prompt from Michael JG Meathook: O*** den.
For those who don't remember, Kate and Isa Whitney are from The Man with the Twisted Lip.
"…nothing on - but her petticoat!" Kate choked out, barely able to get the words out through her laughter.
Mary was in equal hysterics, sitting across from her at the small wooden table. Spending time with her old school friend was the perfect antidote to the loneliness that had crept up on her with John away on a case with Sherlock. She had forgotten many of their school girl antics, but Kate seemed to have remembered them all, and had the most enthralling way of telling them - even better than John's stories, though Mary would never tell him so.
"I hope your husband doesn't mind all the noise we're making in here!" Mary wiped tears of laughter from her eyes. "I haven't heard a peep from him all day."
The mood immediately dampened.
"Isa's out again." Kate smiled bravely, but Mary could see the worry on her face. "He'll be home soon."
"Of course," Mary reassured her, as befitted an old friend. For what else could she do? This was far from the first time Isa had spent the day at an opium den, heedless of all but the allure of the drug. Isa Whitney refused to admit the hold the opium had over him, or the worry he caused Kate. Even John's advice as his doctor was not enough to stop the man. All Mary could do was be there for her whenever Isa finally went too far, and in the meantime, distract Kate from her fears. "Do you remember Sarah and the bicycle?"
Kate's smile was not as wide as before, but it was there. "Remind me?"