(Full Synopsis)

Set in contemporary South Korea, the musical unfolds in a poor hillside neighborhood where three elite North Korean agents live undercover while awaiting orders.

Won Ryu-hwan, a top agent of the 5446 Corps, disguises himself as a mentally slow man named Dong-gu. Alongside him are Rhee Hae-rang, posing as an aspiring musician, and Rhee Hae-jin, a young student sent to monitor him. Though trained as ruthless operatives, they gradually adapt to ordinary life, forming emotional bonds with their neighbors—especially Soon-im, who treats them with maternal care.

As time passes without orders, their rigid loyalty begins to soften. They experience friendship, warmth, and the possibility of an ordinary life—something none of them had imagined.

Their fragile peace is shattered when a sudden command arrives from the North: all agents must commit suicide to erase evidence of their existence. Refusing to accept this fate, the three choose to resist.

What follows is a violent confrontation involving additional agents and government forces. In the end, the characters are forced to confront the cost of loyalty, identity, and the meaning of a life they were never meant to live.