"The King: Eternal Monarch" is a South Korean television series that combines elements of romance, fantasy, and parallel universes. The story revolves around Lee Gon, a modern-day emperor of the Kingdom of Corea, and Jung Tae-eul, a detective in the Republic of Korea. Here's a fictional elaboration of the plot:

In the parallel worlds of Corea and Korea, separated by a mysterious portal, King Lee Gon discovers the existence of multiple universes. As the emperor, he holds the key to this portal, which allows him to travel between worlds. In the Republic of Korea, Detective Jung Tae-eul becomes entangled in a murder case that seems to have connections to the parallel universe.

Lee Gon, burdened by the responsibility of his kingdom, decides to explore the Republic of Korea. There, he encounters Tae-eul and is struck by her resemblance to someone from his past. The two worlds collide as Lee Gon and Tae-eul join forces to unravel the mysteries surrounding the parallel universes.

As the story progresses, they discover a nefarious plot by an antagonist who seeks to exploit the portal for personal gain. This adversary, revealed to be a powerful figure in Corea, manipulates events in both worlds to achieve ultimate control. Lee Gon and Tae-eul face numerous challenges, including political intrigue, family secrets, and the complexities of navigating two very different societies.

Amidst the chaos, a love story blossoms between the king and the detective. Their connection defies the boundaries of time and space, and they must overcome obstacles to be together. Lee Gon's determination to protect both worlds clashes with the villain's relentless pursuit of power, leading to epic confrontations that transcend dimensions.

The series explores themes of fate, sacrifice, and the enduring power of love. Along the way, the characters encounter doppelgangers, each with their own stories and struggles. The fate of the parallel worlds hangs in the balance as Lee Gon and Tae-eul confront the ultimate challenge, testing the strength of their love and their willingness to sacrifice for the greater good.

In a climactic showdown, the protagonists must make difficult choices that will determine the fate of their worlds. The resolution brings closure to the mysteries of the parallel universes, as well as the personal journeys of the characters. "The King: Eternal Monarch" weaves a tapestry of romance, fantasy, and intrigue, leaving viewers captivated by its exploration of the timeless themes of love and destiny across the boundaries of time and space.