In the fifth episode of Our Universe, Yoon-seong, the landlord, arrives at Hyun-jin and Tae-hyung's doorstep. As Hyun-jin opens the door, she instructs Tae-hyung and Woo-joo to hide in the bedroom. However, Woo-joo rushes out, and Tae-hyung follows, tripping on one of Woo-joo's toys and falling down.
Hyun-jin takes Yoon-seong outside and explains the situation. When she returns to the house, she apologizes to Tae-hyung, but he is not as understanding and picks a fight. Later, he receives a message from Amy Choo reminding him of his incomplete assignment. At work, Se-yeon asks Hyun-jin if Tae-hyung may have feelings for her, but Hyun-jin brushes it off.
Meanwhile, Jo Moo-saeng accuses Amy Choo of never giving him credit. She tells him to retire and sign the divorce papers - he's not just her manager but also her soon-to-be ex-husband!
Tae-hyung comes to meet Amy Choo, who says he left his film at her office and took the liberty of developing the photos. She is impressed by his photos of Woo-joo and Hyun-jin, commenting that his photos of Hyun-jin prove his affection for her. She wants to hire him and hands him his first project proposal.
When Hyun-jin comes home, a neighbor asks if she and Woo-joo want to come camping with her family. She agrees and invites Tae-hyung as well. Woo-joo has a great time playing with the other kids, and Tae-hyung takes photos of the whole group. However, Tae-hyung overhears Hyun-jin talking to the neighbor about how she and Tae-hyung are "absolutely not dating." She says things are awkward with him and mentions that he will be moving out soon. Tae-hyung walks away upset, and his behavior turns sour. He soon ticks Hyun-jin off as well.
She goes out for a walk and gets a call from Yoon-seong about some work. She walks off the path to find a better signal and ends up wandering into a restricted area. Back at the camp, the neighbor worries about Hyun-jin not having returned yet. When Tae-hyung remains in a bad mood, she tells him that Hyun-jin actually thinks highly of him. Apparently, he only heard half of what she said. She actually thinks he's a good person and told her neighbor that she will miss him when he's gone.
Tae-hyung realizes his mistake and rushes out in search of Hyun-jin, whose phone goes unanswered. After a while, he finds her in the woods, lost and injured. He guides her to a small cabin as the rain begins to pour, and she thanks him for looking for her. They talk about rainy days, and Tae-hyung confesses that he doesn't like them because they remind him of endlessly waiting for his brother, who never showed up. Hyun-jin tells him to call her if he's stuck on a rainy day, promising to show up for him. He carries her back on the way, and she suggests they be friends now and drop the formalities. Tae-hyung isn't too keen on "friends," but he agrees in the end. Since Hyun-jin is in quite a state, they decide to go home once they reach the camp.
When they reach home, they find Yoon-seong waiting for her. He got worried when their phone call dropped and he wasn't able to reach her. He insists on taking Hyun-jin to the hospital, where she is given antibiotics. In order to thank him, she agrees to buy him a meal the next day.
The next day, Hyun-jin gets ready to go out for lunch with Yoon-seong and Woo-joo. She worries about Tae-hyung, who has woken up with a cold, but he tells her to go. Yoon-seong picks them both up and they go to a restaurant, reminiscing about their college days on the way. Over lunch, Yoon-seong tells Hyun-jin that he wants to get to know her again, like they knew each other in college.
At home, Tae-hyung receives the photos that he took at the campsite. He sees the pictures of Hyun-jin and recalls what Amy Choo said about the camera lens not lying about feelings. Later, he gets a fever and shivers in bed. A flashback shows someone at the orphanage describing how Tae-hyung always falls sick when it rains.
After lunch, Yoon-seong wants to go to a dessert cafe as well, but Hyun-jin worries about Tae-hyung, who isn't picking up his calls. She goes home and takes care of Tae-hyung instead. When he wakes up, he finds her asleep next to the bed. She wakes up and fussing over him again, and this time, he tells her he likes her.
Tae-hyung realized his mistake and ran out in search of Hyun-jin, whose phone was unreachable. He found her lost and injured in the woods and guided her to a small cabin as the rain began to pour down. She thanked him for looking for her and they talked about rainy days which reminded Tae-hyung of waiting endlessly for his brother who never showed up. Hyun-jin promised to be there for him if he ever got stuck on a rainy day. He carried her back on his way and they agreed to be friends without any formalities. Though Tae-hyung wasn't too keen on being friends, he eventually agreed. Since Hyun-jin was in a bad state, they decided to return home once they reached the campground.
When they arrived home, they found Yoon-seong waiting for Hyun-jin. He had become worried when their phone call dropped and he couldn't reach her. He insisted on taking Hyun-jin to the hospital where she was given antibiotics as a thank you gesture, she agreed to buy him lunch the next day.
The next day Hyun-jin prepared to go out for lunch with Yoon-seong and Woo-joo. She worried about Tae-hyung who had woken up with a cold but he told her to go ahead. Yoon-seong picked them both up and they reminisced about their college days on their way to a restaurant for lunch where Yoon-seong expressed his desire to get to know Hyun-jin again like they did in college.
At home Tae-hyung received the photos he took at the campsite and saw pictures of Hyun-jin which reminded him of Amy Choo's words about the camera lens not lying about feelings. Later he fell ill with fever and shivered in bed recalling a flashback of someone at the orphanage describing how he always fell sick during rainy days
After lunch Yoon-seong wanted to go to a dessert cafe but Hyun-jin was worried about Tae-hyung who wasn't picking up his calls so she went home instead to take care of him when he woke up finding her asleep next to him this time around he told her that he liked her
