Touhou Kaikidan - Mystic Square is the fifth game in the Touhou series, released for the Japanese PC-98 in 1998. It is the first game in which Alice Margatroid appears and features four selectable characters - Reimu, Marisa, Mima, and Yuuka. As the final PC-98 Touhou game, Mystic Square's gameplay is the most similar to that of the Windows games.
As so often is the case, something is amiss within Gensokyo. A massive quantity of demons are pouring from a cave high within the mountains. Seeking the source of this invasion, Reimu Hakurei and co. must travel through Makai itself to confront the one behind the problem.