Strangers in the night.

Okay, into Chapter 16 and I've come to the part that I love and dread -- the ritual appearance of Finsbury the Ferret.

My amateur detective, Oliver Swithin, is a children's book writer and, like Conan Doyle before him, he's created a fictional character that he's come to detest. Finsbury crept into Oliver's "Railway Mice" books by mistake, crapped, and refuse to creep out again or indeed clean up after himself. He's the embodiment of all that's vile, which is why he became so popular, among Oliver's adult readers as well. (He's also popular among my readers. Truly.)

Now I prefer to leave most of his evil ways to the readers' imagination. That's largely because anything I come up with is sure to leave them wanting -- I don't do despicable well, despite what my wife will tell you. But even this tip of the iceberg, this glimpse of the dark soul of the beast, is a challenge.

In previous books, Finsbury has appeared in brief extracts from Oliver's stories. This time, I have him popping up in a dream, telling his own creator a few home truths about his physique, his abilities as a lover . . . and conducting a Socratic dialogue about one key aspect of the mystery that Oliver's trying to solve.

I did this once before, and my editor at the time threw her hands up in horror, so it was cut. But I emphasize, this isn't supposed to be "woo-woo"; there's no supernatural delivery of new information. It's just an entertaining way to present Oliver's thought processes, as he belatedly makes connections between the clues that are already plainly on the table. And in this case, he has his reasons for being in denial while conscious.

They say as soon as you know you're dreaming, you wake up. My problem is, how long can you have a conversation with a pot-smoking, Blackberry-using, foul-mouthed talking ferret and not suspect that it's all a dream? (Go ask Alice.)

The (rather old) picture shows me at a book signing, with Diane Plumley's Houdini standing in for Finsbury.