The story is told through several different perspectives. Hase is a young woman living in the
Bay Area in 2016. Josef and Anton are academics in 1930s Austria. When Hase's father goes missing, she sets out to find him only to be drawn into a historical mystery surrounding the Engelhardt Circle, a group of dissident philosophers and mathematicians in 1930s Austria, and the Zedlacher Institute, whose founder claimed to have met a time traveler affiliated with the Circle as a young man. To solve the mystery, Hase follows clues left behind by her father that are hidden in
Wikipedia edits and
deleted articles. == Development history ==