This is a pretty good episode of the series.
It starts out with Brisco and co. being snatched and coerced into working for the Government on an assignment. Although this initially seems interesting, I couldn't really work out why there was so much 'cloak and dagger' to it, especially seeing as Socrates now works for the Government anyway; on hindsight, it did rather seem like story padding.
Straight away I got the reference in the British spy's name – Emma Steed, a mixture of John Steed and Emma Peel in the classic 1960s British series 'The Avengers' (of which I am a huge fan).
Once on the stagecoach, filled with several questionable characters, we – and Brisco – try to work out who the would-be assassin is; and several red herrings are given. I enjoyed this, but didn't find it as good as the hunt for the murderer in the excellent 'Bounty Hunter's Convention' a few episodes previously.
Without giving it away, the twist at the end of the story is a good one, and rounds the episode of nicely.
All-in-all, it doesn't quite make it to being one of my all-time favourites of the series, but it is a reasonable story never-the-less.