I had not seen the mermaid’s swift shadow for the entire journey, but I could feel her presence like the raising of the hairs on your arms before a lightning storm. Why Rodrigo? Why not Cassio, who was clearly there when the slaughter took place, although he couldn’t remember anything but his shame? And if Viv could move out of the water, something I’d little suspected since I’d accused Jessica of being a mermaid changeling, why not tear into the city like a starving orphan into an unguarded larder? I’d assumed that Brabantio, found mutilated in his cellar, had tottered down another passage like the one he’d walled me up in, to the water, where’d she’d struck, but now I wondered if she might not have come in the front door.

“That there is the prison,” I said, pointing to a cracking huge stone fortress that squatted over the harbor. Othello had shown me where it would be on one of the charts, but there would have been no missing it.

“A bit grand for a prison, don’t you think?” said Jessica.

“Was a royal’s palace before, no doubt,” said I. “That’s how it goes. Bit of a revolution, royalty gets imprisoned in the castle, next lot of royals comes along, doesn’t want to live in a sodding prison, builds a grander castle down the way, the old one’s turned into a prison, and so it goes.”