Travelling under my second identity meant I could at last stay in a fine hotel and the fact I was coming and going constantly wouldn't raise any eyebrows. I arrived late in Berlin after a long day of travel, ready to just order in some room service, spending the night reviewing the intel I had before meeting with the local team the next morning.

Enjoying breakfast the next morning, I thought a local contact would just call me to set up details of where I'd be expected or at least be picked up. What I didn't expect was for someone to join me at my table, looking up from the...