Here’s a description for their web site:

Innsmouth Horror introduces several new game concepts to the Arkham Horror board game. Among these are the Personal Stories, a new way for each investigator to contribute. These will provide a bit more of the back story for each investigator, including the 16 new investigators found in the Innsmouth Expansion. Another new feature is the Innsmouth Look deck. These cards represent the dangers inherent in staying in the town of Innsmouth any longer than necessary, and can spell the end for an unwary investigator.

In Arkham Horror, players take the part of investigators discovering clues, fighting monsters and trying to close gates to other dimensions before Cthulhu or another of the Ancient Ones awakens. Arkham Horror is a cooperative game, in which players must work together to succeed. There are currently two large expansions and three smaller expansions for this game.

Read the announcement at this link.