Jwa Yoon-Yi has lived her life with a passive attitude. She has a spirit of devotion and obedience. Nam Chi-Won is the director of HB Company, but he refuses interests of other people and developing relationships. The woman and man meet as secretary and boss.
Competent assistant Yuni covers for her boss's affair and gets in trouble. She keeps crossing paths with indifferent director Chiwon, who finds her odd.
Humiliated by a mistaken affair rumor, Yuni is reassigned as Chiwon's assistant. On day one, he already pushes her to request a transfer.
Chiwon is irritated by Yuni's persistence. Yul offers her a deal for Chiwon's secrets. Yuni's mother seeks a male tenant for her upstairs room.
Chiwon becomes Yuni's tenant, flipping their dynamic. She gives him house rules but gains more chores. Sangmoo schemes to humiliate Chiwon through Yuni.
Yuni debates sharing Chiwon's questionnaire with Sangmoo. She arranges his surprise birthday party and pushes him to join the Best Boss event.
Chiwon knocks over Yuni's birthday cake publicly. As he begins to soften toward her, he steps in when Jangwoo insults Yuni.
Chiwon defends Yuni and enters the Best Boss Award. A Christmas pipe burst causes a misunderstanding with Yuni's mother. Her award presentation goes wrong.
Chiwon collapses and vanishes from hospital. Yuni learns his painful past; he distances himself and asks her to find a new tenant, then feels her absence.
After a kiss, Chiwon and Yuni awkwardly avoid each other. Chiwon secretly probes a product defect tied to Sangmoo. Yuni rushes back after reading his card.
Yuni and Chiwon secretly start dating on her 30th birthday. Yul proposes a joint e-sports project to Chiwon, while Chiwon and Changsu clash over Yuni.
Yuni is unsettled seeing Chiwon with ex-wife Dohee. Sangmoo schemes against his promotion. A fun day together ends with an unexpected guest at the door.
Yuni holds her own against Dohee, earning Chiwon's trust. His mother disapproves of their relationship. Yuni is haunted by memories of a past scandal.
Rumors of Yuni and Chiwon living together spread. He openly admits they're dating. Sangmoo pushes for his resignation as company reorganization looms.
Jangwoo takes charge of reorganization and Yuni is forced back as his assistant. Despite Chiwon's objections, she complies and they promise to reunite.
Chiwon fights to protect his team and bring Yuni back. Yuni plans to get back at Jangwoo for mistreating his assistants.
Yuni returns wearing Chiwon's gift shoes. Bona hands Yuni something secretive after a heart-to-heart. Sangmoo's irregularities are finally exposed.
