After an anomaly suddenly develops near the human settlement on the planet Ross 508B, Captain Chang and her crew aboard the space shuttle ISIS must solve the mystery residing in the red dwarf star system Ross 508. This adventure will test the sanity of the researchers, as well as their ethical and moral integrity, as they must explore an alien environment and make choices that will affect not only their own fates but also the fate of the vast space colony on Ross 508B. "At the Gates of Carcosa" is an independent scenario which, along with "Re-Animator 2508" and "The Oracle of Yuggoth" are the first scenarios I have published from my futuristic setting called "Deep Space." Initially, I will be constructing it based on short and independent scenarios. For the seventh edition of Call of Cthulhu, the setting “At the Gates of Carcosa” introduces 2 new occupations. 6 fresh alien species. 6 built-in characters. 2 maps. 19 pages + 6 character sheets 11 digital handmade illustrations.