Zombicide: Undead or Alive – Gears & GunsExpansion

From BoardGameGeek:

Zombicide: Undead or Alive – Gears & Guns is a steampunk-themed expansion that features brand new Engineer-class Survivors, advanced weaponry, wondrous inventions, and a whole campaign with story-driven objectives and surprises to be unveiled. We live in another world. The world of tomorrow. It took a few decades to set aside our differences. In the end, we stood together as a united nation, and took a step into the future. This is the Age of Steam! Everyday life has been changed, and we offer an American dream to anyone willing to brave new frontiers. Railroads run by the biggest trains connect most cities, making travel fast and secure. Prosperity helps engineers create the most daring inventions. And going West will offer even more opportunities. Wild territories, vast resources: a better life! Steam carries us to these promising lands, protects us against all perils, and heralds a new dawn for civilization. And yet... Yet, rumors talk about frontier towns being erased from the map, of people going mad and hurling themselves into murderous rages. Is it some kind of exotic illness? Who knows, and honestly, who cares? You cannot stop progress. Full steam, in the name of science! Gears & Guns is a campaign expansion. This means its ten missions form a single ongoing story that the Survivors experience, accumulating experience, skills, and equipment as they go. Their actions and choices each Mission may have dire ramifications down the line.