In the premier episode of "Heo’s Diner," we are whisked back to the era of Joseon, where we are introduced to Heo Kyun, a nobleman of exceptional intellect and a compassionate heart, more preoccupied with alleviating the plight of the underprivileged than engaging in the machinations of power that captivated his contemporaries. As a scholar of repute, he dares to petition the king for the abolition of the social stigma attached to illegitimate sons, a courageous act that earns him the bitter enmity of another nobleman, Lee Yi-cheom. Yi-cheom orchestrates Heo Kyun's exile, playing a pivotal role in his banishment.
Even in his exile, Heo Kyun continues to challenge societal conventions, mingling freely with the "lowborn" and utilizing his keen intellect to catch an abundant harvest of fish, which he skillfully transforms into delectable meals for the entire village. One fateful day, he notices an elderly man sitting Lonely in a secluded corner and offers him some fish The old man, an outcast shunned by society, cryptically hints that Heo Kyun's benevolence has saved his life.
Lee Yi-cheom, still wary of Heo Kyun's lingering influence, places him under house arrest. He pays Heo Kyun a visit, attempting to persuade him to comply with an unspecified request, but Heo Kyun steadfastly refuses. Frustrated beyond measure, Yi-cheom confides in Mae-chang, Heo Kyun's lifelong friend, revealing his intentions to resort to drastic measures. In the meantime, he surreptitiously arranges for Heo Kyun's friends—the illegitimate sons—to be apprehended.
Upon learning of the peril his friends face, Heo Kyun escapes. However, Yi-cheom discovers that Mae-chang warned him and orders Heo Kyun's execution. Assassins track him down and strike, but miraculously, the first blow is deflected by the recipe book he had been painstakingly compiling during his house arrest. As a second attack is imminent, the old man from the village begins chanting, and in a blink of an eye, Heo Kyun is transported 400 years into the future.
Meanwhile, in contemporary Korea, we encounter Eun-sil, a fiery office worker who refuses to tolerate injustice. She stands up to her boss for assaulting a coworker, only to find herself terminated once again. Later, she bumps into a drunken Heo Kyun and, due to a misunderstanding, inadvertently leads him to believe that the world he has arrived in is hell. Convinced that he is in the afterlife, Heo Kyun somehow manages to persuade Eun-sil’s mother, who runs a modest diner, to provide him with sustenance.
The next morning, Heo Kyun awakens in the bustling metropolis of modern Korea and marvels at what he perceives as a utopia—an era brimming with abundance, where food is plentiful for all, and freedom reigns supreme beyond his wildest imagination. Elsewhere, we discover that Eun-sil's mother's humble diner is situated directly across from a high-end restaurant helmed by a renowned chef, Lee Hyeok, who bears an uncanny resemblance to Lee Yi-cheom.
Intrigued by the brewing competition, Lee Hyeok embarks on a mission to gather intelligence about her rival diner. As the episode draws to a close, a tender moment unfolds where Heo Kyun, oblivious to Yi-cheom's past betrayals, mistakenly identifies Lee Hyeok as Yi-cheom and embraces him warmly, unaware of the deception lurking in the shadows of their shared history.
