Holmes and Watson are on their way back to Baker Street from a freshly wrapped-up case when they hear shrieking from around the corner, and naturally they charge around the corner to see what's happening. What's happening turns out to be a giant snake with a mirror for a face. They get the woman it has cornered out of the way, and Watson goes for his revolver, but before he can bring the snake down it gets its face over both of them and they're somewhere else.
"Blue and grey, not overly complicated." Holmes nods agreement from where he's been semi-lurking behind Watson.
"We're from very far away. It's good to have someone else there who speaks our first language. Also, we lived together before we came here because " groping for concepts, then groping for words " there weren't enough houses."
"It's complicated . . . people are harder to make, there, and harder to make for specific things like building houses, and also it's very hard to get from one round to a different round, so hard to find enough space."
He wrinkles his forehead. "I don't understand either."
"That sounds unpleasant. I'm glad you got it worked out!"
"We will, thank you! We'll bring the plate back tomorrow."
Once they're both back inside and eating cookies, Watson remarks, "How odd to think that if we were inverts, we could get married here and nobody would so much as find it surprising. We aren't, of course--just a strange fact."
"Yes. We aren't inverts, so it is of no importance, but all data is worth having."
Cookie-eating. Silent, contemplative cookie-eating.