I found this trickier than I had thought when, after reading the preamble and before solving any of the clues, I'd (correctly, as it turned out) worked out what and who. But getting from there to a completed grid took 4 hours. I take my hat off to Serpent for a very clever new approach and for the layers needing to be unpicked to get to the obvious target. This ought to be high up in the annual awards.