Four scenarios lead players to heights of terror. “BLACKSAT” follows a team of elite NASA pilots and a pair of strange civilians into space in 2010. They may discover truths about mathematics and physics beyond all human wonder and fear. “Night Visions” follows a Marine squad in Afghanistan in 2011. A diplomatic patrol takes them into Gath Valley, a corner of the country that everyone tries to ignore—a valley of deep shadows, blinding sun, and endless hungers. In “Sick Again,” a team from the Centers for Disease Control flies to rural Arizona to investigate a strange viral outbreak. That takes them to unnatural threats beyond time itself. “Wormwood Arena” brings together survivors from the prior adventures as Delta Green recruits. A harmless-seeming Kansas cult’s new pamphlet sports a sigil of unnatural portent.