Once part of Santa Ana's Mexican Legions the Lost Army was dispatched northward to investigate a mythical 'black rock' with magical porperties found up in the hills. Presumed dead for over 50 years they have now returned with a burning hatred for the living and their full complement of siege weapons now twisted into thunderous and deadly Hell Cannons!

Each of the Mission Packs offered in the Add-Ons menu is a themed adventure set including a new Enemy type new cards themed for those Enemies a set of new Missions involving them and a new Objective Room Map Tile that like the other map tiles in the game is double-sided. It has an Old West Mine side and an OtherWorld side both for use with the themed Missions of the set.