The first episode of "You and Everything Else" commences with Ryu Eun-Jung receiving an unsettling revelation from Director Choi about Cheon Sang-yeon. Sang-yeon, a CEO and a highly successful one at that, has just won a prestigious Baeksang Award. In her acceptance speech, she publicly calls out Eun-jung, a stark contrast to the earlier, unseen words where she vowed to ruin Eun-jung's life.
Eun-jung's demeanor towards Choi is brusque, admitting that their once close friendship ended in a "messy breakup." Choi presses Eun-jung for the truth, and we're given glimpses of the story in the present timeline. Sang-yeon seemingly stole Eun-jung's project, "Echoes of Summer," which was initially hers. When Sang-yeon took it, it propelled her company, Swallow Pictures, to the big time. Eun-jung still harbors resentment and actively avoids any of the studio's movies.
We then flashback to 1992, the first day of the Second Semester at Ilyeong Elementary School. Twelve new students are transferred in, including Sang-yeon. Her grandfather was once a prominent minister in the Korean government, and she comes from the best private school in the area. As a result, she's effortlessly the top student here. Eun-jung's teacher plays favorites and has a clear bias against her neighborhood kids, forcing them to sit on the floor and study when there aren't enough desks.
Eun-jung's life with her mother in a semi-basement in a rough part of town is a constant struggle to make ends meet. When she tastes the luxury of a standard apartment with multiple bathrooms, it's like a glimpse of heaven. She leaves a sticker inside the closet, reading "You're so lucky," and it turns out that Sang-yeon moves into that very apartment.
At school, Sang-yeon, the class president, is strict and even smacks Eun-jung's hands when she stands up for herself. This sets the stage for a grudge that carries over to the new school year. Eun-jung now has new friends and becomes a know-it-all, lashing out during dodgeball and hitting Sang-yeon in the head. But her frustrations simmer when she ends up in the company of Ms. Yoon, a kind teacher who has a soft spot for her.
Ms. Yoon knows Eun-jung's story and speaks to her about her family, encouraging her not to be too disheartened by her father's absence. He left when she was 8, and it was a painful experience for her. Ms. Yoon encourages her to fill this empty space so she doesn't feel so lonely and even suggests she starts a personal diary.
Life is not easy for Eun-jung, who works delivering milk to apartment complexes on behalf of her mother. Naturally, she bumps into Sang-yeon's father at the complex, and though the girls don't say anything to each other, Eun-jung is embarrassed all the same. When one of the kids at school, Kim Seong-kwon, makes fun of Eun-jung at school about the milk, she immediately suspects Sang-yeon and confronts her about it. Sang-yeon swears she didn't do it, and in a surprising twist, we learn that Ms. Yoon is actually Sang-yeon's mother.
After the incident with the sticker earlier on, Ms. Yoon actually hit Sang-yeon for striking another child. Given they deliver milk to the family, Eun-jung's mother wound up telling her about this incident, adding another layer to the already complex dynamic between the girls.
Shortly thereafter, Sang-yeon is transferred to a recently established school nearby. A small incident unfolds when her school crush, Jun-ho, chooses to sit with Eun-jung instead of her, setting off a subtle but significant rift between them. Yet, in a twist of fate, Eun-jung finds herself developing feelings for Sang-yeon's older brother, Sang-hak.
Flashing forward to the present, Sang-yeon calls Eun-jung and requests a meeting. It emerges that she is terminally ill with an aggressive form of cancer. Despite her condition, she has a favor to ask of Eun-jung: she hands over an envelope containing a boarding pass to Zurich, revealing her wish for Eun-jung's assistance in the act of euthanasia.
