She stays—not as secretary Kim, but as Young-joon’s partner.

Present day: Young-joon’s older brother, Lee Sung-yeon, returns from abroad. He’s kind, gentle, and strangely interested in Mi-so. Too interested. He buys her flowers, knows her favorite dessert, and whispers, “Do you remember the cellar?”

Determined to win her back, Young-joon does something unprecedented: he asks her to teach him to be a better boss. But during a team dinner, a childhood trigger surfaces—a forgotten trauma involving a chandelier, a kidnapping, and a mysterious boy named “Lee Sung-hyun.”

Young-joon, terrified of appearing weak, denies everything. But Mi-so has learned to read him. The way he flinches at swinging lights. The way he never sleeps in total darkness. The way he once, years ago, asked her to tie his tie extra tight—like a comfort.

“Vice-President Lee, I’m resigning.”

Sung-yeon, defeated by their bond, apologizes and moves abroad. The company adapts. And on the last day of her “resignation notice,” Mi-so doesn’t leave.

Flashback: Twenty-two years ago, young Mi-so was kidnapped alongside a boy from a wealthy family. They were trapped in a dusty room for days. The boy protected her, sang to her, and promised to save her. When rescuers came, she was found alone—the boy’s identity remained a secret.

In a rain-soaked office after hours, Young-joon finally breaks. “I remember everything. The ropes. The darkness. Your tiny hand in mine. I promised to marry you so you wouldn’t be scared.”

They date. Publicly. Disastrously. Young-joon tries to be romantic but buys her a building instead of flowers. Mi-so teaches him to eat street food and laugh at himself. His narcissism softens into devotion.

He kneels—this proud, ridiculous man—and says, “Don’t resign. Don’t leave me again. I’m nothing without my secretary. But more than that… I’m nothing without you.”