In Borderlands, each player runs a kingdom. The kingdoms are grown by adding new lands to the capital and new creatures to the lands. As each kingdom grows, it becomes more powerful -- but it also becomes more vulnerable as its borderlands grow as well.
Each turn, land and creature & feature cards are drawn. Power cards, Gold, Food, and Resources are gathered from the lands. Armies are deployed to opposing kingdoms, capturing new lands from their borderlands.
Ultimately, one player will save up enough power cards to create an artifact for his kingdom. If this artifact is brought back to the capital, the player wins.