A Beacon in the Night

From publisher blurb: This is an adventure for Cepheus Engine. For two hundred years the human settlers on Sarmahalos III have walked up the mountain overlooking their primary city and wondered at the alien spire at the top. No one knows who built it or why. But professor Xia Sokolov thinks that he knows the answers. And he offers to hire the travelers to do a little leg work to find out if he is correct.