The Dark Mod is a free and open-source software first-person stealth video game.
The Dark Mod takes place in a classic gothic steampunk world. This includes a crossover of elements of fantasy, the Late Middle Ages, the Victorian era and the Industrial Revolution. Although set in a very similar world to that of the original Thief series, the mod does not use any of the original Thief intellectual property. – https://en.wikipedia.org/wiki/The_Dark_Mod
