She reenters the main wing as if she still has a lookout, like every other night; which of course she doesn’t.

“Miss Macnair.”

Flat of foot and red of hand, Proserpina considers her tactical options. She can probably outrun Miss Havisham: this is at best a stall. She can open with a jab to “thanks to an eyewitness” plexus, followed shortly “all hours of the night” and a right hook, which should finish things up “explain your behavior?”

Frowning in thought, Proserpina suddenly realizes she’s expected to answer.

“Oh,” she says, “no, but I do have the other thing. Er, blackmail?”