Lee Hong-jo possesses an enigmatic box, facing challenges in opening it. Jang Shin-yu gets disappointing medical news, asks Lee Hong-jo a favor. Lee Hong-jo attempts bonding with coworkers.
Sin-yu finds himself unable to resist the desires of his heart, but a third party complicates the matter; Hong-jo pursues a romantic interest of her own.
While Hong-jo and Sin-yu both experience illnesses, a sinister plot forms in the dark. Later, they share a tender moment of connection, present and past.
As Hong-jo and Sin-yu grow closer, news of their relationship spreads. But as unsavory information circulates in the midst, Hong-jo navigates a minefield.
Hong-jo experiences a vision after Sin-yu rescues her from a dangerous situation. Hong-jo discovers the true reason behind Sin-yu's worsening symptoms.