The Silver Twilight is an international organization dedicated to the destruction of the human race. As brave Investigators, you must piece together passages from esoteric books, shards of ancient artifacts, and puzzling letters to discover the Silver Twilight's loathsome goals. This multi-chapter adventure begins in Boston and spans the globe. The Investigators must survive and conquer the mind-shattering monsters and minions of the Cthulhu Mythos. Come, journey through awesome realms of reality, and match your wits and sanity against diabolical lurkers in SHADOWC OF YOG-SOTHOTH! This scenario book includes three new adventures for the CALL OF CTHULHU role-playing game. SHADOWS OF YOG-SOTHOTH is a seven-chapter tale of horror and suspense. Also included are two bonus scenarios: one is suitable for beginners and the other is perfect for experienced Investigators. Eight pages of Player Information include corrections and additions to the CALL OF CTHULHU rules and a very special centerfold !