Earthborne Rangers Legacy of the Ancestors Board Game Explained

About Earthborne Rangers: Legacy of the Ancestors, from BoardGameGeek:

A campaign expansion, includes a full playset over 250 new Ranger and Valley cards and 1 campaign guide. Legacy of the Ancestors features a new story arc that utilizes both the cards and map from the core set as well as the new cards and new maps from the campaign expansion. In it, you'll journey beyond, above, and below the Valley to explore strange new places and forge new paths.