Isolated from the world by a mystical barrier, shrine maiden Reimu Hakurei and magician Marisa Kirisame live relatively peaceful lives in the land of Gensoukyou, when they find themselves transported beyond the boundary and into the unfamiliar territory of the outside world. After a chance encounter with Sumireko, a human girl obsessed with Gensoukyou and all its wonders, our protagonists eventually find their way back home—but now with an unexpected guest in tow. Sumireko's arrival not only heralds chaos for Gensoukyou, but also for the outside world and beyond! It's up to Reimu and Marisa to unravel the mysteries that threaten their home and restore peace to the lands.