Episode 5 of Twinkling Watermelon starts with a flashback from when Eun-gyeol was a child. He recalls drowning in the ocean and calling out to his father as his parents and Eun-ho play by the beach. Eun-gyeol recalls how his father had said he would always save Eun-gyeol first as he was the person who connected their family to the outside world.
As he drowns, Eun-gyeol wonders how his father would’ve been able to help him when he himself wasn’t able to hear Eun-gyeol and save him. Just then, Eun-gyeol’s father jumps into the ocean and pulls him out, saving his life. That night, Eun-gyeol chats with his father and learns how after losing his hearing, Yi-chan’s visual senses have amplified.
The episode jumps back to the past where Eun-gyeol is worried that Yi-chan has already lost his hearing. Seeing how Yi-chan could still hear him and had no scar on his shoulder, Eun-gyeol comes to the realisation that his father was yet to lose his hearing. He tries to prevent the accident in order to change Yi-chan’s fate.
Eun-gyeol asks Yi-chan to be very careful for the rest of the year knowing how his father had lost his hearing when he was in 11th Grade. Yi-chan is confused by Eun-gyeol’s concerns and worries that Eun-gyeol is gay, and is coming onto him. Yi-chan runs back to the boarding house, trying to escape Eun-gyeol.
That night, Eun-gyeol warns Yi-chan, asking him to be very careful for the next 1 year. Meanwhile, Seo-kyung’s boyfriend Ji-hwan and her classmate – Sang-a come to drop her off at the airport as she moves to the United States. Se-kyeong is dejected to see that Chung-a was not there to bid her farewell. Seo-kyung’s father – Choi Hyun watches her leave for the States.
At school, Yi-chan and Ma-joo wondered what they could do to start their band as they needed 3 more students to join them as soon as possible.
Just then, Eun-gyeol shows up at the school and challenges the school band’s guitarist, Hyun-yool, to a riff-off. The battle ends with Eun-gyeol victorious and the school band members – drummer Si-guk, pianist Se-bum and Hyun-yool agree to join Yi-chan’s band.
The teacher is surprised to see that Yi-chan has managed to get 5 more students, including Eun-gyeol as their guitarist, to be a part of the band – First Love Memory Manipulators. The original members of the school band try to kick Yi-chan out as he isn’t able to work a single musical instrument.
After Eun-gyeol’s pleas, the band members ask Yi-chan to learn how to play an instrument in three days. Eun-gyeol agrees to teach Yi-chan how to play the guitar but the only condition is that Yi-chan has to bring his grades up. Yi-chan’s grandmother is very happy with Eun-gyeol’s help. She thanks him for being her grandson’s guardian angel and Eun-gyeol gets emotional, knowing the old woman was his great-grandmother.
The next day, Chung-a gets a letter from Se-kyeong who tells her she has safely arrived in the States. In the letter Se-kyeong wonders if anyone would really miss her. Chung-a thinks of Yi-chan and goes to the bookstore looking for him. Eun-gyeol shows up at the same bookstore and finds Chung-a there but does not recognise his mother’s teenage self immediately.
Ma-joo meets him on his way out of the bookstore and the two go back to the boardinghouse. There, Eun-gyeol is shocked to see that Yi-chan has finished all of his homework without a word. Eun-gyeol feels bad for his father knowing that starting the band now would have no impact on his relationship with Se-kyeong as she had moved to the States.
However, we see Se-kyeong returning back to South Korea. She goes to her house and gives herself a makeover. That night, Eun-gyeol has a bad dream and wakes up to see Yi-chan trying to work the guitar himself. Eun-gyeol helps Yi-chan tune the instrument and gives his father his first guitar lesson.
The next day, everyone at the boarding house notice how similar Yi-chan and Eun-gyeol are to each other and Grandma pointed out how they looked like they were father and son. At school, Yi-chan learns that Se-kyeong has moved to the States for good.
At the same time, Se-kyeong collects her old branded clothes and decides to thrift them in order to make some cash. That noon, Yi-chan goes to a guitar shop owned by Se-kyeong’s biological father – Choi Hyun. He looks for guitars for his father when all of a sudden he spots Se-kyeong.
Eun-wol goes out of the guitar shop to see Se-kyeong and learns that she is back in South Korea for good. She tells Eun-gyeol that upon arriving in the USA, she had learned that her adoptive father was cheating on her adoptive mother. This had sent her adoptive mother into another depressive episode.
Tired of bearing the burden of her mother’s mental struggles, Se-kyeong had fled back to South Korea to end her own life. Eun-gyeol is shocked by the confession but Se-kyeong asks him to keep the news of her arrival in Korea a secret. At the same time, the rest of the band members find Yi-chan playing the guitar in the music room.
The members are shocked by Yi-chan’s talented singing as he sings about his failed love for Se-kyeong. After he goes back home, Yi-chan goes to his part-time job at the ice cream shop. He finds Chung-a there and scolds her for writing a fake note. Yi-chan furiously explains that Se-kyeong had insulted him in front of all her friends. He calls Chung-a “deaf”, not knowing how she really did not have the ability to hear.
Chung-a is shaken up by the comment and flees away. Meanwhile, Yi-chan’s boss tells him that Chung-a is actually deaf and the high schooler is embarrassed by his words. Yi-chan thinks about the comment all day and rushes outside with an umbrella when it starts raining in order to see if Chung-a is still around the ice cream parlour.
However, Yi-chan runs into Se-kyeong who happens to be right outside his workplace. Moreover, Eun-gyeol realises that since his parents had met in the sign language class, he needed to get his mom to meet Yi-chan before he lost his hearing. Eun-gyeol hopes to make the two fall in love and tries to look for her.
He runs into Chung-a, who is crying by the phone booth, still upset over Yi-chan’s comment. Eun-gyeol hands out his umbrella to Chung-a and flees to the ice cream shop as Chung-a follows after him. The episode ends with both Chung-a and Eun-gyeol watching Yi-chan and Se-kyeong together.
As interesting as the story of this show is, the timeline makes it a bit confusing. I have a feeling that no matter what Eun-gyeol will do, Yi-chan is bound to end up having an accident that will cause him to lose his hearing. On the other hand, there is also a possibility of Yi-chan catching feelings for Chang-a.
The ending of this episode puts that theory up for question but we can expect a love triangle between Yi-chan, Chang-a and Se-kyeong. It is also possible that Se-kyeong catches feelings for Eun-gyeol which makes things a lot more chaotic for the present timeline.