Oh Jin-shim—better known by her stage name, Oh Yoon-seo—takes a forced break from acting after a scandal derails her career. Hoping for a comeback, she turns to a top screenwriter who agrees to help under one unusual condition. Soon after, ace lawyer Kwon Jung-rok learns that Oh Yoon-seo has been assigned to the firm as his secretary.

Jung-rok discovers that Jin-shim was not at fault for the missing documents. He apologizes, but Jin-shim is still upset and drinks too much at the welcome party. When she sees Jung-rok arrive, she loses her composure and confronts him head-on.

Jin-shim finally gets a chance to prove herself as a secretary, but her excitement quickly fades under the crushing workload. Meanwhile, Jung-rok takes on the case of a high school student accused of fraud. Jin-shim steps in to help, but the case grows more complicated as the student keeps lying.

Jin-shim joins Jung-rok on weekends to study law, but it is simply their time together that she enjoys the most. Her good mood shifts when she notices how unusually warm he is toward prosecutor Yu Yeo-reum. Meanwhile, Seung-hee, a college student being stalked, turns to Jung-rok for help. While gathering evidence, he learns that Jin-shim was once stalked too.

Jin-shim begins to realize that her time with Jung-rok is starting to mean more to her. However, when he puts Yeo-reum first again, jealousy gets the best of her. Hoping to understand Jin-shim's feelings, Jung-rok asks her directly at a company dinner. Around the same time, he takes on the case of Lim Yun-hee, who is on trial for murdering her husband.

Jung-rok and Jin-shim work late nights preparing for Lim Yun-hee's trial. One evening, they get stuck in an elevator and finally confront their feelings. When a male friend comes to pick Jin-shim up, Jung-rok feels unsettled. Later, while searching for clues at the crime scene, they come under sudden attack.

Jin-shim struggles to sleep after Jung-rok's ambiguous confession. She waits for him to make the next move, but Jung-rok—more fluent in legal codes than romance—does not follow through. Embarrassed for getting ahead of herself, Jin-shim has one too many drinks and calls him with a drunken confession.

Jin-shim hears that Yeo-reum was Jung-rok’s first love. She visits him to learn the full story and meets Se-won, a charming prosecutor. Se-won is stunned to learn that Jung-rok’s girlfriend is none other than the "Goddess of the Universe," Oh Yoon-seo. Meanwhile, a group of new interns liven up the mood at Always Law Firm. Under Jun-gyu's lead, the team sets off on a company trip.

Jung-rok becomes noticeably sweeter around Jin-shim. While handling a case involving malicious online comments, he learns that she has dealt with the same throughout her acting career. Hoping to give her a break from the spotlight, he plans a special date just for her. Meanwhile, a video of middle school bullying surfaces online, and the victim names Eun-ji’s daughter Jin as the aggressor.

Jin-shim and Jung-rok begin their romance at work, and despite his inexperience in dating, Jung-rok's warmth continues to catch her off guard. But just as everything starts to feel right, Jin-shim senses an unsettling gaze on her. When she uncovers who has been following her, she is left shaken.

The stalker, Lee Kang-joon, finally appears before Jin-shim and Jung-rok. Jin-shim opens up about the trauma he caused and tries to move on with Jung-rok’s support, but healing is not easy. Hoping to ease her pain, Jung-rok plans a thoughtful date. As their bond grows stronger, Lee Kang-joon, driven by jealousy, begins to threaten those close to Jin-shim.

Lee Kang-joon grows increasingly reckless in his twisted obsession with Jin-shim. Jung-rok teams up with Se-won to track him down. As Jin-shim's final week at the law firm approaches, each day they share feels more precious. But when news of her return to acting breaks without warning, Jung-rok and the entire firm are caught off guard.

Jin-shim struggles with her first true heartbreak and finds it hard to accept the separation. The next day, she stops by the law firm using the excuse of picking up her things, but Jung-rok greets her with a cold response. A month later, both are fully absorbed in their work. Then, the mother of the real culprit in the Lim Yun-hee case shows up at Always Law Firm and causes a scene.

Tensions erupt between Jung-rok and Jun-gyu over a controversial case. As public outrage grows, Jung-rok resigns. Jin-shim is devastated by the media storm and her helplessness. Just then, she receives an urgent call from the Always Law Firm.

Jin-shim and Jung-rok reunite after finally acknowledging their true feelings. Not wanting her to leave, Jung-rok asks her to spend the night. As Jin-shim's schedule grows busier, he steps in as legal counsel for her drama to stay close. The couple steals moments for secret dates on set and at home—until Jung-rok comes across a kiss scene in her script.

Love begins to bloom at Always Law Firm, as Jung-rok and Jin-shim share blissful days together. However, when Jin-shim's overseas shoot is suddenly moved up, they are faced with a farewell that feels all too final. The couple try their best to make the most of their last day together count.