In Crimson Seas, you will obtain Maps to new far-off lands beyond the borders of Valeria allowing you to import trade Goods from Araby to increase your victory points, purchase Tomes of great power to augment your resource production, rescue captured Nobles from the villainous Amarynth Empire, and plunder the wealth of the Cursed Isle. Beware the monsters of the sea, though, as they increase in strength, sowing chaos throughout all of Valeria.
Along the top of the play area is a new game board called "The Islands". To access the Islands you need to use a new action called "Sail" and to sail, you've got to spend one map token, then you can access Araby to gain Goods, Nae Aerie to gain Tomes, Exekratys to retrieve lost resources, and Amarynth to rescue captured Noble's.
This expansion has new icons, new tokens, new mechanics, new card types, and new cards for all the existing card types.