Elder Sign: Unseen Forces - Rules of Play says:
Unseen Forces brings a fresh challenge to the efforts of the investigators in the world of H.P. Lovecraft’s weird fiction. The museum harbors artifacts that draw the attention of horrible beings, and the unfathomable wills of these creatures make themselves known in the form of blessings and curses. New Ancient Ones, monsters, and investigators accompany the introduction of these powers, and the entrance of the museum has been remodeled, adding new locations and options for the beleaguered investigators.