Point:
MC suddenly wakes up and gets shocked when his father comes home with a new wife and five stepsisters. So far, there’s no romance at all between MC and the sisters. The story focuses on family drama, where MC tries to adjust to his new life, until he’s finally accepted as their older brother.
Character:
MC: Miyanaga Rikuto (2nd year high school, 16)
Sister 1: Miyanaga Chinatsu (2nd year high school, 16)
Sister 2: Miyanaga Mio (1st year high school, 15) *Twin
Sister 3: Miyanaga Karin (1st year high school, 15) *Twin
Sister 4: Miyanaga Fuuka (2nd year middle school, 13)
Sister 5: Miyanaga Sorane (1st grade elementary, 6)
Father: Miyanaga Mukai
Stepmother: Sugiyama Natsuki → Miyanaga Natsuki
Childhood friend: Asahina Meme
Teacher: Asahina Aru
Friend: Hiruoka Atsushi
Friend: Yaku Shinobu
Note: Eisei Private High School, cat groomer, Shibainu Hana, Haruhara, Miyanaga Yuki
★ On a school holiday, Rikuto wakes up late, which is unusual for him. He’s used to living alone because his father often travels for work. His mother passed away when he was in 5th grade.
While making breakfast, he hears the doorbell and sees movers bringing stuff inside. Confused, he thinks it’s the wrong house. Then his father arrives and casually says he just got married, and starting today, his new wife and daughters will live with him. Rikuto is completely shocked.
★ A white car arrives, and a woman steps out, followed by her daughters. Rikuto realizes he now has not only a new mother, but also five stepsisters.
★ During introductions, the stepmother introduces herself as Natsuki. The eldest daughter, Chinatsu, is 16 and in the same grade as Rikuto. Since Rikuto is older by a month, he becomes their big brother.
Then Mio and Karin, twin sisters, followed by Fuuka and the youngest, Sorane.
★ After that, the parents leave to buy dinner. Chinatsu immediately sets rules, saying that even if they are now family, they’re still basically strangers.
They divide rooms and living rules. The house has three floors, and Rikuto is banned from going to the third floor where the sisters stay. They also set different bath schedules to avoid contact.
★ Later, Rikuto accidentally falls on top of Mio while carrying drinks, spilling milk on her. Chinatsu sees this and instantly threatens him with a stun gun, warning him not to touch her sisters. The atmosphere becomes awkward afterward.
★ At school, Rikuto meets Meme and Atsushi. He keeps the secret about his new family. A transfer student is coming, and it turns out to be Chinatsu, who ends up sitting next to him.
She introduces herself and warns everyone not to mess with her. When Atsushi mentions her sisters, she slams him down and threatens him, making everyone afraid.
★ At lunch, her sisters show up, instantly drawing attention because of their looks. The Miyanaga sisters quickly become famous in school.
Route Mio
★ Rikuto sees Mio talking to a cat and helps return it to its owner. Mio explains the collar issue, showing her knowledge about cats.
She reveals her dream of becoming a cat groomer. Rikuto shares his past with his dog Hana, who passed away, making him afraid to have pets again. Mio comforts him.
★ After that, Mio forgives him for the earlier accident and starts calling him “oniisan.” Karin later interrupts them.
Route Karin
★ At night, Karin sneaks into Rikuto’s room and teases him. She ignores the house rules and says her relationship with her boyfriend doesn’t matter.
She asks Rikuto to check the trash the next day.
★ Rikuto finds out the sisters rely on convenience store food. He secretly cooks with Mio, and everyone loves the food.
But Fuuka and Sorane overhear the truth.
Route Fuuka
★ Rikuto hears noise upstairs and breaks the rule to check on Fuuka.
She reveals she was practicing dance, and her elegant speech is fake, hiding her real dialect.
She asks to practice dancing in Rikuto’s room, and he agrees.
Route Sorane
★ Rikuto visits Meme’s house and later walks home with Chinatsu. He talks about feeling lonely since his mother died and envies warm families.
They get caught in the rain and race home.
★ Sorane arrives and asks for help, leading to an awkward situation where Chinatsu comes out of the bathroom unexpectedly.
Chinatsu tries to hit Rikuto, but he dodges everything due to his training.
Last Route Chinatsu
★ Chinatsu loses contact with Fuuka and Sorane and starts searching for them.
★ Rikuto learns her trauma, Fuuka was once almost kidnapped, and Chinatsu got badly hurt trying to save her. Since then, she became overprotective.
★ They track a suspicious car and chase it to an abandoned factory. After a fight, they defeat the kidnappers.
★ Rikuto gets injured protecting Chinatsu, but they eventually resolve everything.
★ Back home, it turns out Fuuka and Sorane were just buying a birthday gift. Chinatsu gets emotional and runs away.
★ Rikuto finds her by the river and tells her to stop carrying everything alone.
For the first time, Chinatsu accepts him as her older brother.