Julian, the cold and arrogant president of Sinclair Holdings, is harsh and demanding to his civilian assistant Chloe. He keeps a strict class boundary and confines her by his side, treating her as a substitute for his deceased first love to heal his emotional wounds.Chloe endures all the grievances in silence without complaint. Her only purpose is to earn high salary to cover the huge medical expenses for her comatose boyfriend in a suburban sanatorium.When the global chief jewelry designer competition opens, Julian’s half-brother attempts to seize power. Under huge pressure, Julian publicly abandons and dismisses Chloe to protect his status.Chloe leaves decisively and participates in the competition with her own strength. Witnessing her thorough transformation, Julian is consumed by jealousy and tries every means to stop her. However, he finally uncovers the cruel truth: he has never been loved by Chloe. From beginning to end, **he is the only substitute in this relationship**.