The Three Fairies of Light-Sunny Milk, Luna Child, and Star Sapphire-have more opportunities than ever before to engage in mischief since they moved into the large tree near the Hakurei Shrine. However, their actions may now lead to severe consequences if they anger Reimu Hakurei, the youkai exterminator of Gensokyo. Despite this serious threat, the trio continue to use their quirky abilities to annoy anyone they target. Their prankishness includes harmless illusions, inconsequential thievery, and even actions that benefit Gensokyo's residents.