You play co-op as disciples of Christ in the 1st Century AD trying to evangelize the ancient Mediterranean world. The goal is to take over a number of regions by controlling all the cities in that region. You do this by rolling dice based on the current level of influence in the city. (Similar to risk, mechanically)
Players can take 3 actions per turn and have a character card with a special ability (similar to Pandemic or Forbidden Island)
There are Global and Local event decks that hurt/help you along the way.
You lose if the world influence controls X number of cities before the players control Y number of regions. Y is variable based on game difficulty set by the players, and X is variable based on the number of players.
There is a free print and play version along with a PDF rulebook at the link above you want to peruse.