Since ancient times, Japan has upheld the tradition of the 12 Zodiac signs. Eto-musumes (Zodiac girls), who have the appearance and behavior of the animals of the Zodiac, are pure hearted messengers who act as a bridge between humans and the gods. Every 60 years, the “ETM 12” tournament takes place in Tokyo’s Akihabara district, where aspiring girls from all over Japan gather for the chance to become the next zodiac sign.
Episode 1
Amato Takeru, a high school student, has just moved to Akihabara. He's chosen a house with cheap rent, but with one particular imperfection: a hole in the living room floor. When he peeks into it, a girl pops out... And so begins the hectic life of Takeru and the cat Eto-musume, Nya-tan.
Episode 2
Takeru awakes in the morning to the smell of meat cooking, and finds Nya-tan preparing breakfast over a blazing fire. More and more Eto-shin girls have appeared from the hole in the living room, posing a threat to the peace and quiet of Takeru's life in his new home.
Episode 3
Nya-tan and Uri-tan have made new homes for themselves on Takeru's property (without asking him), and the three of them go shopping for new furniture. Nya-tan has no money, so she tries to get an advance on her paycheck at her part-time job...
Episode 4
Having been saved by Uri-tan, Nya-tan returns to the maid café Eto, where Usa-tan criticizes her character. A meeting of the Eto-shin whose characters don't stand out enough begins!
Episode 5
Takeru is stuck in bed sick, and the sheep Eto-shin, Mei-tan, determines that what he has is no ordinary cold. With all the Eto-shin going wild as Takeru's Sol/Lull rages out of control, Nya-tan and Mei-tan decide to battle the unknown virus.
Episode 6
Nya-tan tries to find some way to get Sol/Lull Seals without effort. Her master Shima-tan catches her trying to bribe Inu-tan and Key-tan with their favorite treats. Can Nya-tan win the battle with her enraged master?!
Episode 7
Nya-tan messes with Shar-tan's hair ornament and ends up petrified. Shar-tan says she'll need the antidote in order to return to normal and takes Takeru on a journey to find it, but they end up in a place filled with Nya-tan's memories...
Episode 8
It's time once again for the annual Takamagahara Commemorative Maid Café Eto Manager's Cup! Uma-tan is determined to breathe new life into this event of the Eto realm that has steadily lost popularity, but Nyaa-tan's intrusion throws the race into chaos!
Episode 9
Piyo-tan is angry when Nyaa-tan ridicules her beloved hobby, shogi. Nyaa-tan gets cocky and challenges her to a Sol/Lull Seal battle, and Piyo-tan chooses the battle method... but Nyaa-tan has no idea what the rules are, so she begs Takeru to train her!
Episode 10
Mo-tan is still chasing Nyaa-tan around everywhere. Apparently, her love stems from a memory the two of them shared long ago. Meanwhile, Chu-tan is on the move in her mission to destroy Nyaa-tan... so Mo-tan rises to defend Nyaa-tan.
Episode 11
Reincarnation is impossible?! When Nya-tan has trouble accepting what happened to Mo-tan in her battle with Chu-tan, Mo-tan entrusts the last of her strength to her beloved Nya-tan. Meanwhile, the Eto-shin do everything they can to save Chu-tan from being engulfed by the negative Sol/Lull gathering within her.
Episode 12
After receiving the last Sol/Lull Seal she needed, Nya-tan challenges Chu-tan to battle. What was the technique Nya-tan came up with to help Chu-tan long ago? After two thousand years of passing each other by, the two of their hearts will come face-to-face once more!
