In the eleventh episode of Our Universe, the scene opens with a passionate kiss between Tae-hyung and Hyun-jin at the airport. He assures her that he's not going anywhere, and she soon realizes her mistake. A few feet away, Amy Choo tells Manager Jo not to go, and they make up as well.
Back at home, Tae-hyung confesses how much he missed staying with Woo-joo and Hyun-jin. They have a heartwarming dinner together, and their love is now in full bloom.
The next day, Hyun-jin meets Yoon-seung and confesses her feelings for Tae-hyung. Yoon-seung looks downcast but eventually says he's happy she's with a good person. He also reveals that he saw Tae-hyung at Woo-joo's daycare recital. He then wishes her well and they part ways.
Hyun-jin meets Tae-hyung and Woo-joo at a playground and asks them about the daycare recital. He expresses his doubts about being good for her and Woo-joo. Hyun-jin tells him that she doesn't just date anybody and encourages him to believe in himself. He's overjoyed to hear that they are officially dating and proudly announces her as his girlfriend. The neighbors, who happen to be there, cheer for them.
However, Hyun-jin asks him to keep their relationship a secret at work since they already caused a scandal once with the viral video. That evening, Woo-joo refuses to let Tae-hyung go home. They go out for a walk to put Woo-joo to sleep, and Tae-hyung asks Hyun-jin if he should move back in. She happily agrees.
The next day, Woo-joo's daycare teacher tells Tae-hyung that Woo-joo has been saying "no" and "I don't want" a lot. She explains that it's natural for kids to develop opinions and want to be independent, but advises that Tae-hyung and Hyun-jin not indulge all his whims. At work, Hyun-jin's team learns that they are in charge of an overseas expo. However, Yoon-seung says he will be handling it himself.
Hyun-jin returns home to a warm embrace from Tae-hyung and Woo-joo. As Tae-hyung attempts to plant a kiss on Hyun-jin, Woo-joo interrupts the moment, bringing their attention back to the little one. In her mailbox, Hyun-jin discovers a summons from a family court, informing her of an upcoming interview and hearing to determine her fitness as Woo-joo's guardian. It turns out that custody does not automatically vest in her.
Over the next few days, Hyun-jin and Tae-hyung prepare for the court proceedings. At work, Hyun-jin confides in Se-yeon about her happiness with Tae-hyung, but also admits that their parenting styles are vastly different. Tae-hyung adheres to strict rules and routines, whereas Hyun-jin is more flexible.
On the weekend, the trio embarks on a trip, despite a few hiccups that test their patience. Nevertheless, they have a wonderful time together, and Hyun-jin vows to take Woo-joo out more often.
On their return journey, they stop at a rest area to change Woo-joo's diaper. They suddenly realize that Woo-joo's beloved dinosaur toy is missing. While searching for it, Hyun-jin lets go of his hand for a moment, and in that fleeting instant, he disappears. Tae-hyung and Hyun-jin frantically search for him, even making an announcement. Finally, a woman finds him in the parking lot and returns him to Hyun-jin and Tae-hyung's relieved embrace. Hyun-jin blames herself for the incident, but Tae-hyung consoles her and urges her to focus on the upcoming interview.
The next day, Hyun-jin is late for her guardianship interview due to unforeseen work commitments at the office. She is surprised to see that her interviewer is the same woman who found Woo-joo in the parking lot earlier. The woman expresses concerns about Tae-hyung's father's involvement and the fact that they almost lost Woo-joo recently. Her verdict is that they are not suitable to raise Woo-joo.
