Undercover is an unusual mission with a little bit of jank here and there, but is an enjoyable change of pace. To steal the last Talisman, Garrett decides to infiltrate the Hammer temple housing it while disguised as a novice.

You're free to explore the compound without having to hide from the Hammers, so long as you stay out of specially designated private areas, making the mission a genuine casing experience. You get to plan your strategy ahead of time. It's the first of its kind in the Thief series.

The Hammer temple itself is set out nicely, with a logical layout and plenty of interconnections, and it's nice to see the day-to-day lives of the Hammers. Overheard conversations and readables hint at political maneuverings in the Hammer order and give a bit of interest to what is, at its heart, a big scavenger hunt. Because the Talisman is locked away behind physical barriers and magical ones, and you've got to discover the means to unlock both.

Your quest will take you through guard barracks, kitchens, priests' private bedrooms, torture chambers and somewhat confusing catacombs. While it's easy to get around, and figuring out how to orient yourself is a fun challenge, I would have liked a little bit more verticality. There's very few opportunities to jump, climb, or mantle. I also found the "off limits" areas, marked off by red Hammer symbols, to be a bit finicky. And a few of the clues to the hidden objects you have to find in order to open the Talisman cage are, on a first playthrough, frustratingly obscure.

Overall though, this mission is above average both in terms of concept and design. It's not among the very best of the best, but it's one I look forward to on every playthrough.

And as a random observation, the briefing text and readables in the mission suggest that the Keepers and the higher-ups in the Hammerite order are acquainted with each other. I find this an intriguing bit of lore.