(Full Synopsis)

Set across 1992 and 2012 at the Blue House, the musical unfolds as a dual-timeline mystery, where a present-day disappearance triggers the reemergence of an unresolved case from twenty years earlier.

In 2012, preparations are underway for a diplomatic concert when the president’s daughter and her bodyguard suddenly disappear. The incident recalls a similar disappearance from twenty years prior, prompting Chief of Security Jeong-hak to reopen buried memories.

The narrative shifts to 1992, when a young Jeong-hak begins his career alongside his colleague Mu-yeong. The two form a close bond despite contrasting personalities. Assigned to protect a mysterious female interpreter connected to a diplomatic event, both men gradually develop emotional ties to her.

As tensions rise, it is revealed that the government seeks to eliminate the woman due to sensitive political knowledge. Mu-yeong chooses to protect her and flee, while Jeong-hak remains bound to duty. Their conflict escalates as loyalty, friendship, and love collide.

Ultimately, Mu-yeong sacrifices himself in an explosion to ensure her escape, leaving behind letters that shape the emotional core of the story. Jeong-hak, burdened by guilt and misunderstanding, carries this unresolved trauma into the present.

Back in 2012, the disappearance of the president’s daughter mirrors the past. Through clues hidden in musical scores and memories, the truth behind both timelines is uncovered. The missing individuals are found, and long-held misunderstandings are resolved.

In the final moments, past and present converge symbolically as Jeong-hak confronts Mu-yeong’s memory, finally reconciling with the past and achieving emotional closure.