Princess Jellyfish centers around Amamizukan, an apartment building in Tokyo, where the only tenants are otaku women, and where no men are allowed. While each character has her own particular fixation, the protagonist is Tsukimi Kurashita, whose love of jellyfish stems from memories of her dead mother taking her to an aquarium and linking the lace-like tendrils of jellyfish to the dresses of princesses. Tsukimi hopes to becomes an illustrator and is an awkward girl terrified of social interaction, attractive people and the prospect of formal work. The other tenants of Amamizukan are the same, being mainly fujoshi, NEETs and refer to themselves as the "Amars" (nuns). Tsukimi meets the stylish Kuranosuke Koibuchi, the illegitimate son of a politician, who cross-dresses to avoid the obligations of politics and to feel closer to his mother.