In the debut episodes of The Eccentric Romance, the story begins with a chilling scene. A young man wakes up in an isolated location, shocked to find a bloodied sickle and a dead, stabbed man beside him. Alarmed by the sound of approaching police sirens, he quickly flees the scene.
As the scene shifts, we meet Jay and his friend Sung Hoon, who are late to their lecture. Despite their tardiness, their striking looks catch the attention of the girls in class. Through a voice-over, Jay introduces himself as a Thai student studying in Korea with his friend Sung Hoon, a Korean language major. They’ve been close friends for eight years.
The class receives an assignment to capture a portrait of their true selves, prompting both Jay and Sung Hoon to commit to getting into shape for the perfect photo. Sung Hoon, already in peak condition as the ace of the basketball team, doesn’t need to worry, but Jay feels insecure when he sees two well-built PE majors. Sung Hoon takes him to a gym, where they meet Seo Ji Won, a fellow Thai major who has a crush on Sung Hoon. She helps them register for the gym, forming an immediate bond with Jay.
Once inside, they encounter Chae Jin Wook, the gym trainer—who, is the same man involved in the mysterious murder from the beginning. Jin Wook, a lover of Thai culture, is especially kind to Jay, who admires Jin Wook’s strong physique. Although Jay pushes himself during his workout, he becomes exhausted, leading to a playful moment where Sung Hoon massages his leg, much to Jay’s embarrassment.
As they leave the gym, Sung Hoon grows suspicious of Jin Wook when he notices him carrying a small, mysterious sack. Later that night, a drunk Jay tells Sung Hoon he’ll call him “hyung” (big brother) if he doesn’t get into shape. Jay even attempts to kiss Sung Hoon, but the latter panics, especially when Jay lies on top of him. The tension between them escalates as Jay teases Sung Hoon, asking if he has feelings for him, which Sung Hoon adamantly denies.
The next morning is awkward as Sung Hoon behaves strangely, while Jay has no memory of the previous night’s events, wondering if he upset his friend. Later, Jay and Seo Ji Won watch Sung Hoon play basketball. While Jay reflects on how much Sung Hoon has changed, Seo Ji Won is only interested in watching sweaty guys. She encourages Jay to hire a personal trainer to achieve his fitness goals.
At the gym, Jay decides not to disturb Sung Hoon, who is focused on his own workout, and instead accepts training from Jin Wook. The two form a friendly bond, but Sung Hoon seems visibly jealous and irritated by their interaction.
That evening, Jay compliments Jin Wook, but Sung Hoon dismisses the praise. When Sung Hoon warns Jay that it won’t be easy to build muscle like Jin Wook, Jay gets sulky. To make amends, Sung Hoon offers to buy Jay’s favorite food. While at the restaurant, they learn that the recent murder is connected to their school. Jay vows to get stronger to avoid becoming a victim, joking that he’ll befriend Jin Wook for protection. Sung Hoon denies being jealous, but Jay’s continued admiration for Jin Wook’s physique causes Sung Hoon to snap in frustration, even refusing to share his food with Jay.
Later, during a lecture, Sung Hoon dreams of being complimented by Jay, only to wake up to Jay scolding him for staying up late playing games. However, Sung Hoon’s exhaustion stems from overworking himself, driven by jealousy over Jay’s praise for Jin Wook. Sung Hoon is determined to look better than Jin Wook.
As Jay playfully fixes Sung Hoon’s hair, Sung Hoon, overwhelmed by Jay’s good looks, almost kisses him—only for Jay to slap his forehead and leave, asking him to join him for food. Sung Hoon, confused by his feelings, follows after him.
Meanwhile, back at the gym, Sung Hoon witnesses police officers questioning Jin Wook about the man who died, Kim Jun Shik, adding a layer of mystery to Jin Wook’s involvement in the murder.
