I liked the museum mission from Thief: Deadly Shadows (Still Life with Blackjack) which was one of the very best in that game, but I rarely seen fan-missions with the same premise. The second Mystic Gems mission is one of them. It is not very large (albeit much bigger and longer than its prequel, Unlucky Soul) but densely packed with guards, quests, subplots, and again guards... The main goal here is to retrieve (again) the Mystic's Heart which Garrett acquired earlier in his Bonehoard "expedition". After series of exchanges and bargains The Heart ended up in the Baronial Museum in city of Bohn.

The layout of the museum is not extremely complicated and provides good balance between openness and easyness of navigating (despite lack of descriptions of rooms in map). Locations are interconnected, and there are at least three different exits to the museum, and a lot of transitions inside. But I didn't lost, the layout is mostly logical. And what I like in Heart of Bohn most is the sense of mystery and dreamlike atmosphere which is supported by its ambients (including some from TDS), and competently used custom visuals. The mission sometimes looks almost like Thief 3! The story itself is decent albeit being unfinished (the 3rd mission was planned, but - and it is very unfortunately - was never released).

My main issues are small: the sewer section around museum is a bit empty and too large, and also one of unmarked (but mandatory) tasks with obtaining the particular key is a bit misty formulated (the indication of key placement is very vague and imprecise). Overall, those shortcomings are not significant and mission is worth to play (but it is preferable to play the prequel first).