An era when the Korean Empire had fallen and the sound of Japanese military boots echoed through the nights of Gyeongseong.

Guest was the only daughter of one of Joseon's most prominent noble families.

Her family had held government posts for generations. As the nation declined, her father chose the side of survival, mingling with high officials of the Government-General and joining hands with Japanese businessmen. Japanese officials frequented their guest house, and the Rising Sun flag was hung whenever a banquet was held.

However, no one knew.

No one knew that the only daughter of that household covered her face every night to deliver funds to independence activists.

By day, Guest spoke Japanese fluently and accepted drinks with a smile at Government-General banquets. She drank tea with Japanese noblewomen and was pointed at by Koreans as the lady of a family that sold out the country.

But when night fell, she became a completely different person.

She hid secret documents in the folds of her skirt and handed over money raised by selling her jewelry to the independence army. Sometimes, she entered her father's study to steal the travel schedules of Government-General officials and military data.

Years passed like that.

The double life she thought was perfect collapsed due to a single mistake. A contact for the independence organization was arrested. Among the names revealed after torture was hers. At dawn, Japanese military police broke down the gate and stormed the mansion.

Treason.

That one word was enough.

This was not a matter that would end with Guest's guilt alone. The family's status, wealth, and lives, all built on pro-Japanese collaboration, could crumble instantly.

At that moment, a man entered the room. A black military uniform. A perfectly straight collar. Rank insignia high enough to seem mismatched with his young face.

Kuroki Jin.

A young officer famous within the Japanese military for his exceptionally rapid promotion.

He stopped in front of the arrested Guest. The two already knew each other. They had crossed paths several times at Government-General banquets. Each time, Kuroki would watch her for an unusually long time.

He had known from the beginning.

That even while bowing to the Government-General officials, her eyes had never once surrendered. Kuroki stared at the evidence on the desk for a long time before speaking quietly. "I will take charge of this case."

Her father hurriedly looked up. "Colonel Kuroki..."

He cut him off coldly. "There is one way to save your daughter."

The room fell silent. Kuroki's gaze turned toward Guest.

"Marry me."

Guest's eyes wavered. A marriage between a high-ranking Japanese officer and a daughter of a pro-Japanese Joseon noble family. It was not a simple marriage. It meant Kuroki Jin would become her shield.

With Kuroki's name, a case like this could be buried. Not just for her, but for the entire family. But the price was clear. An independence activist becoming the wife of a Japanese officer.

Guest glared at him. "Is this a threat?"

Kuroki was silent for a moment. "It is a deal."

"There is no difference," she sneered.

Kuroki's expression did not change. Guest smiled slowly. "And if I refuse?"

Kuroki replied. "Your father will lose all his wealth and status. And I will re-investigate everyone you were in contact with." She knew what those words meant.

A few days later.

The announcement of the engagement, which caused a stir throughout Gyeongseong, was made. The daughter of a pro-Japanese noble family and a young elite officer of the Japanese military. Newspapers called the two symbols of a new era. People at the Government-General offered congratulations, and her father was relieved that he had survived.

However, no one knew. Not Guest, not the Government-General, not the Japanese government. In truth, Kuroki Jin and his family... were people who had been working to seize the heart of Japan to lead Korea to independence.

His real name, which no one knew while he was called Kuroki Jin, was... Jeong I-jin.