Nocturnum 1: Long Shades
The Nocturnum campaign introduces a new alien evil to your Call of Cthulhu game. "Long Shades"¸ the first book in this campaign¸ contains a wealth of background material on this malignant new force¸ as well as three complete adventures: Snowflake Valley¸ The Madness of The Twilight Queen and Stillness. Each highly-detailed adventure can be played as part of a longer campaign¸ or as a stand-alone adventure in your current campaign.
"Long Shades" is a postmodern campaign sourcebook for the Call of Cthulhu roleplaying game. The background and adventures detailed in "Long Shades" are also easily adaptable to most other horror roleplaying systems.