From the announcement:
Fantasy Flight Games is proud to announce Forsaken Lore, an expansion for Eldritch Horror. Forsaken Lore adds over two hundred new cards to Eldritch Horror, including over one hundred new Encounter cards, twenty condition cards, and fourteen new mysteries.
The fate of the world grows even more uncertain as the malignant influence of Yig, the Father of Serpents, extends across the globe. Previously defeated Ancient Ones attempt to reclaim the world once again, forcing Investigators to solve new mysteries to keep them at bay. All the while, terrible new Epic Monsters and dangerous new Encounters keep Investigators racing across the globe to stave off the collapse of the world.