From the post:
Masks of Nyarlathotep introduces a brand new way to experience games of Eldritch Horror with its campaign mode. Campaign mode sets up a world that's threatened by a continuous onslaught of Ancient Ones, tasking the investigators to undertake six sequential games. Losing a single game to any one of these horrifying forces spells certain doom for mankind, and will cost you the entirety of the campaign. Can the investigators stop this barrage of Ancient Ones from destroying our vulnerable world during this unique cosmic event?