Episode 1 of "Our Universe" unfolds with an introduction to Woo Hyun-jin and Sun Tae-hyung, two individuals navigating their respective struggles in life. Hyun-jin, a diligent food delivery worker, and Tae-hyung, a photographer's assistant, share a compelling story of perseverance and resilience. Hyun-jin's older sister, Hyun-joo, who shares a heartwarming dinner with her sibling, knows of Hyun-jin's unfulfilled dreams of securing a full-time job and assures her that her time will come.
Later in the episode, Hyun-jin discovers an engagement ring in her sister's purse. Confronting Sun Woo-jin, Hyun-jin's sister's boyfriend at the police station, she gives her blessing as a representative of the family and suggests a meeting of the families.
Meanwhile, Tae-hyung is at a club with his team when his boss makes derogatory comments about his background from an orphanage and lack of degree. Driven by anger and a desire for independence, Tae-hyung quits on the spot, leaving him in dire financial straits. His friends advise him to sell some of his belongings, including a fancy lamp that catches Hyun-jin's eye.
As Hyun-jin, Hyun-joo, and Woo-jin go wedding dress shopping, Hyun-jin notices that her sister adores a wall lamp from a magazine. Desperate to give her sister a memorable wedding gift, she sets her sights on purchasing the lamp but is deterred by its steep price.
Tae-hyung agrees to sell his lamp on an app called Pimang. When Hyun-jin sees the post and tries to purchase it, they engage in a heated negotiation that ends with the lamp's bulb breaking. Their confrontation leaves them on bad terms, but Hyun-jin's phone ends up in Tae-hyung's possession. Through the pictures and messages on her phone, he discovers that Hyun-jin's sister is marrying his long-lost brother.
A flashback reveals a young Tae-hyung weeping as his older brother walks away. The next day, Tae-hyung storms into the family meeting, accusing his brother of abandoning him at the orphanage. In a fit of anger, he tells Woo-jin they shouldn't see each other again. A heartwarming flashback shows Woo-jin celebrating Tae-hyung's birthday by buying him a camera and new shoes, then taking him to an orphanage where he promises to return soon.
The scene unfolds, depicting Hyun-joo and Woo-jin's wedding day. Unfortunately, Tae-hyung fails to show up. The narrative then skips three years forward. It's revealed that Tae-hyung has abandoned his photography career to take up a corporate job, which has proven fruitful as he's just purchased an apartment for himself.
On the contrary, Hyun-jin is working in an office but continues to be overlooked for full-time positions. When Hyun-joo suggests moving back home, Hyun-jin takes offense, believing her sister doesn't have faith in her abilities. She storms off and doesn't respond to Hyun-joo's texts for several days.
Meanwhile, Woo-jin receives a text informing him that his father is being released from prison and considers reaching out to Tae-hyung. He and Hyun-joo are on their way out when a tragic accident occurs - a truck hits their car, claiming both their lives.
We see Hyun-jin grieving at the funeral. Soon after, Tae-hyung arrives and it's there that he meets Woo-joo, Hyun-joo and Woo-jin's young son. When Hyun-jin sustains an injury with a ligament tear, Tae-hyung steps up as the chief mourner and ends up taking care of Woo-joo until she returns. Later, one of Woo-jin's colleagues raises the issue of Woo-joo's custody since Tae-hyung and Hyun-jin are his only relatives. Tae-hyung refuses to be involved with his brother anymore, but Hyun-jin agrees to raise him. Tae-hyung says his goodbyes and leaves.
The scene transitions from the somber atmosphere of the funeral to the tender moments between Tae-hyung and Woo-joo as he takes on the role of a guardian. Through this transformation, the story explores the complexities of family dynamics, the unexpected twists of fate, and the resilience of the human spirit in the face of adversity.
