I was sitting on the terrace of the Ateljée Bar, atop the Hotel Torni, some years back, drinking absinthe while being interviewed for a Finnish fanzine. The Atelier, as it translates to, was a spy bar during the Cold War. I doubted that at first because, surely, such a place would be closely watched? But staring down at the bright orange-tiled rooftops of Helsinki and the narrow near-black streets and alleyways between them, I could not help but feel cunning and ruthless. It explained so much – including why spooks would gather where they could be easily spotted. The sort of people they were pretending to be – diplomats, trade reps, industrialists – would not be able to keep themselves away.Something like that applies to the spy genre. I’d never before even considered working in it. But when I got the invitation to be a guest writer for The Witch Who Came In From the Cold, I was right there.Nobody ever said so, but I could see that my episode took place in a hiatus in the plot, a week in which inspectors from Langley and Moscow descend upon Prague for their annual audits, and magic has to be temporarily set aside. That way, if it turned out I could not write to spec and on schedule, it could be quietly dropped while Lindsay, Ian, Cassandra, Rose, and Max closed ranks and picked up the slack. I admired the craft of that. It made me doubly determined not to let them down.So I was cunning and ruthless.I put the characters in bad places. I had them make terrible choices. I let them blunder blindly past each other. I gave Tanya an apartment that was the twin of a Moscow flat on the Garden Ring where I’d once stayed. (Did you know that in Soviet times everybody in the USSR had identical flats with identical furniture? Astonishing but true.) I let Gabe enjoy the worst aspects of office jobs I’d held down. I’d been given a series bible with information about the music and literature and art of the times but I found I did not need it. I’d lived through them all.It was astonishing how at home I felt in this world.Non-writers often imagine that plot is difficult to dream up. Not so. Given so rich a universe to play in, filled with such vivid characters to torment, the trick is to keep from overcramming the text with incident. I originally had a subplot about a honey trap, involving an American senator’s daughter, an international youth conference, and a strutting young Russian lothario who annoys the living snot out of Tanya – both for his braggadocio before the conference and for his mooncalf behavior after he falls in love with his target. Poor Arnie Lytton had a heartbreaking backstory. And there was a lot more business with the Soviet clerical staff who, trust me, were not women you’d want to get angry at you.I am a professional. I discarded all that and the episode is the better for it. Though I will always regret losing the way Tanya’s eyebrows shoot up when the young romantic explains that the original Summer of Love was held in Moscow in 1917.There are few things a writer likes better than coming up with a title that looks straightforward but in retrospect is ironic. I called my episode “A Week Without Magic,” because the biggest challenge facing the characters was going for seven days without their best and most effective tools. But of course there was magic all the way through the episode – both literal and figurative. The writing team for what we informally called the Cold Witch Project created a magic theater and gave it a cast of players. Then, for a season they gave it to me and let me pretend it was my own. To me, that was the real magic.I shall always feel grateful for that.And cunning and ruthless, too, of course.