OniAi
Season 1
201212 episodes
After 6-years' separation, Himenokouji Akito reunites with his twin sister Akiko and they live together once more. However, in the interim, Akiko had developed a serious case of bro-con, romantic feelings for Akito. It doesn't stop there as Nikaidou Arashi, the student council president of his new school, vice-president Nasuhara Anastasia, and Sawatari Ginbei Haruomi, who followed Akito all the way from Kyoto, all move in with him one after the other.
Episode 1
Brother Love
Oct 5, 201225m
Akiko moves into a school dormitory with her brother Akito, when he transfers to her school. Owing to her brother complex, Akiko has a crush on Akito. With both of them in student government, will Akiko be able to share him with the other council members?
Episode 2
Indecent
Oct 12, 201225m
Akito catches Akiko reading a trashy romance novel. Akito, having trouble settling in to in his class, is given firsthand lessons in the concept of "tsundere"from both Akiko and Anastasia. Akito and his longtime friend Ginbe get into an argument.
Episode 3
No Bra
Oct 19, 201225m
Akiko asks Akito for help changing her light. Akito has his hands full maintaining the dorm, from fixing the plumbing to repairing the doors. The girls have differing opinions over allowing Akito to take in the laundry. Akito helps Anastasia settle in.
Episode 4
Naked
Oct 26, 201225m
Akito brings home a special dessert, just for Ginbe to enjoy. Akito continues to fix up Anastasia's room, and the two of them discuss her hobby of collecting stuffed animals. Arashi has the girls take a bath together, to help them bond together better.
Episode 5
Sexual desires
Nov 2, 201225m
In a student government meeting, the council members discuss what they are going to call Akito. Kaoruko proposes that Akito write a short story to be published in a women's magazine. She grows concerned for him when she learns his sibling is a sister.
Episode 6
Mayonnaise & chicken
Nov 9, 201225m
Kaoruko reads the latest installment of Akito's love story. She decides to stop by the dorm, where she meets the others, and asks them whether they think Akito has a sister complex. The council decides to separate Akito and Akiko into separate rooms.
Episode 7
Chippai
Nov 16, 201225m
Akiko is upset over not being consulted before Arisa, who claims to be Akito's fiancée, was hired as dorm manager. Later that day, Arashi proposes that Akiko and Arisa compete in a contest, to see which one of them is the better little sister to Akito.
Episode 8
Colorful
Nov 23, 201225m
The girls all go to find new swimsuits even though summer is still in the distance. They try frilly ones, sexy ones, and cute ones. Then, Arashi proposes a contest to show of their new goods and Akito must decide which one impresses him the most.
Episode 9
Nii-Nii
Nov 30, 201225m
Akito follows Gin to the back of the school building to find out why she is acting so suspiciously. When Akito suddenly falls sick, everyone fights over who will nurse him back to health. They decide to take turns treating him how they see fit.
Episode 10
“Gindama”
Dec 7, 201225m
During her turn nursing, Ginbe reminisces about Akito's transfer to her school and how they first met. After Akito recovers he has to choose the winner of the contest he had no idea about. What is the prize and what will the winner do with such a chance?!
Episode 11
Ephemeral
Dec 14, 201225m
Unable to find her panties, Anastasia decides to go commando for the rest of the day. Arisa gets frightened by something she sees outside of the dorm and the group decides to investigate the source. All the while, Kaoruko sleeps in a feverish slumber.
Episode 12
It's love
Dec 21, 201225m
Everyone gets separated and Akiko is left alone with Nasuhara. While contemplating her panty dilemma, Nasuhara reminisces about her first meeting with Akiko. What will happen to Akito and his crew of crazy girls that sleep under the same roof?