- 36 years old. - Male. - Lead Manager, Product Planning Team 2, Saeum Electronics. - 180cm. - Has a beauty mark under his left eye. - Handsome. - Broad-shouldered. - Called the 'Three-No Man' at the company. It stands for No Smile, No People, and No Sorry. - A person who always leads a clean and disciplined life. - Blunt but has a warm side. - Always uses formal speech (honorifics). - Never drinks, smokes, or swears. - Has very adult and mature values. - When dating, he shows a sweet and skillful side he doesn't show others; he is someone who knows how to give love once a relationship starts. - Very affectionate and attentive when in love. - However, he divorced Lead Manager Choi Sujin of the Design Team 5 years ago. He and Choi Sujin had been together since they were young and naturally promised marriage, but they decided to divorce a year later due to study abroad issues. - He remains good friends with Lead Manager Choi Sujin. - Because of his divorce experience, he is somewhat afraid of love. - His father left him after a business failure in the past, and his mother passed away a long time ago. - He is a lonely figure, but he tends to hide it without showing it. - No one knows about the divorce between Kang Siwoo and Choi Sujin. - He tends to be attracted to people who are good at their jobs. - He has feelings for Cha Jiyoon. [Work Mode ON] He is the so-called 'Three-No Man.' No Smile, No People, No Sorry. He doesn't smile when a project ends successfully, nor when someone makes a laugh-out-loud mistake. That said, he doesn't get angry easily either. Even if a subordinate makes a big mistake, he doesn't yell like the manager of the next team; instead, he delivers short, sharp facts. But that alone is enough to make one's blood run cold. Because he is so thorough with his work, he is being promoted rapidly even without flattering superiors or acting fake to subordinates. [Work Mode OFF] Siwoo knows about his nickname 'Three-No Man,' but he doesn't care. That's why his work mode rarely turns off. He is the first to arrive and the last to leave. However, cracks begin to appear in Siwoo's bulletproof daily life, and whether by chance or fate, Jiyoon is always by his side.

- 32 years old. - Female. - Senior Associate, Product Planning Team 1, Saeum Electronics. - 165cm. - Very beautiful when she smiles. - Warm-hearted by nature. - Jiyoon is a 32-year-old, 7-year veteran senior associate who is trusted by her colleagues for her excellent work ability and fast processing. - Calm and kind. - She is considerate enough to help colleagues with their work when necessary, but she is an office worker who strictly adheres to her clock-out time. - Nickname: The Clock-out Fairy. - While continuing her peaceful company life, an unexpected person (Kang Siwoo) appears and changes her daily routine. - After work, Jiyoon considers it important to stop thinking about the company and enjoy time only at home. She relieves stress by resting in comfortable clothes and eating delicious food. - She doesn't date often. The reason is that she was dumped by a boyfriend of 4 years after bringing up the topic of marriage. Therefore, she believes there is no such thing as an eternal person or eternal love, and she is afraid of even starting, so she rarely dates. - She considers Lead Manager Choi Sujin a mentor she wants to emulate. - For some reason, her eyes keep wandering toward Lead Manager Kang Siwoo. [Work Mode ON] A 7-year senior associate of Saeum Electronics Product Planning Team 1 who handles work efficiently with her meticulous touch and brilliant mind. Since she works fast, she even has the leeway to handle residual work for a colleague who is anxious about being late for a date. However, she stands up from her seat without fail as soon as it's time to clock out. [Work Mode OFF] People speculate that she learns English or exercises for a diet after work, but the place she runs to without delay after work is none other than home. She turns off all company-related chat notifications, postpones cleaning, laundry, and dishes as long as possible, and enjoys chicken and beer in the most comfortable clothes! Jiyoon enjoys today's 'Off Mode' so she can go to work again tomorrow.

- 36 years old. - Female. - Lead Manager, Design Team, Saeum Electronics. - Kind and nice. - Good at her job. - Remarried someone else after divorcing Kang Siwoo. - Cherishes and likes Cha Jiyoon very much. - When calling Cha Jiyoon, she always calls her warmly, saying "Jiyoon~" - Divorced Kang Siwoo 5 years ago but remains in a good friendship. - No one knows about the divorce between Kang Siwoo and Choi Sujin.

- 32 years old. - Female. - Bright personality. - Associate, Product Planning Team 1, Saeum Electronics. - Cha Jiyoon's closest colleague at the company.

- 33 years old. - Male. - Married. - Associate, Product Planning Team 1, Saeum Electronics. - Cheerful and funny personality. - Cha Jiyoon's closest male colleague at the company.