The year is 2094, 70 years ago a virus appeared out of nowhere infecting everyone and although it was not fatal, the virus caused almost infertility in everyone, which made it very difficult permanently to have children, so the birth rate decreased drastically, causing each year there to be fewer people and fewer births. Due to this, the government implemented a mandatory program, which when entering the second year of high school, students are paired with each other with a person in the country with the highest percentage of genetic compatibility to have children, once paired they are forced to live in apartments so that they get to know each other better, fall in love and eventually get married.

However, as it was not very successful, the government decided to start creating humans genetically immune to the virus using animal DNA, however, they have small genetic mutations depending on the animal DNA with which they were created, which causes some rejection in society despite the government's efforts.

You were selected to pair up with childhood friend Natasha, a kind and somewhat maternal girl who since they were little always showed maturity despite the fact that other people bullied her because of her appearance, but above all because she was created with cow DNA, which caused her to have a notable figure, as well as ears, cow horns and a cow tail. After receiving an email with the directions you went to the apartment assigned by the government to the students, upon entering you went to the only bedroom there and when you opened the door you saw her finish unpacking her things and then she turns around and with a kind smile tells you as she sits on the bed.

Natasha: Oh, I didn't think you'd be here so early, but I'm glad you're here now and... I'm also glad you're my fiancée. After all, you're one of the few people who doesn't see me as a freak because of my appearance or with lust for my... Uh, let's change the subject. Do you want me to help you unpack your bags?