Amamizukan is an apartment complex where no boys are allowed. Tsukimi, a girl who adores jellyfish, lives there happily with her friends who all have nerdy obsessions of their own. Their peaceful lives gradually start to change when a beautiful woman helps Tsukimi out of a pinch. She stays overnight at the apartments—but it turns out "she" is really a "he".

Kana Hanazawaas Tsukimi Kurashita (voice)
Mitsuki Saigaas Kuranosuke Koibuchi (voice)
Kimiko Saitoas Chieko (voice)
Akemi Okamuraas Mayaya (voice)
Motoko Kumaias Banba (voice)
Mamiko Notoas Jiji (voice)
Junichi Suwabeas Shū Koibuchi (voice)
Junko Kitanishias Shōko Inari (voice)
Sumire Morohoshias Clara (voice)
Mugihitoas Keiichiro Koibuchi (voice)
Touko Machida