Following the events of the second spring snow incident, Gensokyo passes through a brief summer and welcomes the arrival of autumn. The annual Moon Capital Exhibition, a beloved Mid-Autumn Festival tradition, opens as scheduled — but this year feels different. As the full moon rises and casts its strange light across the land, an enormous curtain descends silently over all of Gensokyo. Before anyone can react, the night sky has completely stilled. Youkai rarely glimpsed before have appeared in the open. And the Exhibition banquet is drawing nearby fairies in droves.