Young Master Lu, Your Flash-Married Wife has Run off Again!

Mu Nanyan, a fashion design senior at Beijing University, attends what she believes is an interview for a designer assistant position at Dingsheng Group. Instead, she is told by the handsome executive Lu Yiran that the position is actually for interviewing to become his wife. Lu Yiran proposes a contract marriage: one year of cohabitation, after which they will divorce with Mu Nanyan receiving five million yuan and an apartment. Having just been broken up with by her boyfriend Su Muyang and wanting to escape her abusive stepmother and half-sister in the Mu household, Mu Nanyan agrees. They register their marriage the next morning and sign a prenuptial and cohabitation agreement that prohibits sharing a bed and requires secrecy.

Mu Nanyan moves into Lu Yiran's luxurious villa, where she is treated with respect by the staff, a stark contrast to her life at the Mu residence. Meanwhile, she discovers her late mother Shen Yi left behind a trust fund and a USB drive, and learns from her mother's attorney that Shen Yi made her will just one day before her death in a car accident. Mu Nanyan becomes suspicious that her mother's death was not accidental and begins investigating. She also learns from her father Mu Feng that he is not her biological father, having discovered this through a DNA test after she was born. Mu Feng claims he kept her because he grew attached, but Mu Nanyan remains skeptical of his sincerity.

At Dingsheng Group, Mu Nanyan misses her first day of work because she detours to meet the attorney. Lu Yiran, assuming she stood him up to meet another man, becomes angry and has her blacklisted from the company. When she returns home and tries to call him, he blocks her number. She spends days investigating her mother's past, finding inconsistencies in her father's story about his affair with Lin Wan. She notes that Mu Feng never divorced Shen Yi despite claiming their marriage was loveless, and that he continued raising a child who was not his biological daughter.

Mu Nanyan's investigation leads her to suspect that her mother's death and the family's secrets are connected. She finds that her mother had no known parents and that the inheritance distribution in the will seems designed to benefit someone other than Mu Nanyan. As she digs deeper, she realizes that the contract marriage with Lu Yiran may provide her with resources and protection to uncover the truth. Lu Yiran, despite his initial coldness, begins to notice Mu Nanyan's resilience and intelligence, and his feelings toward her start to shift from suspicion to curiosity. The story sets up a dual narrative: Mu Nanyan's quest to solve her mother's death and Lu Yiran's gradual emotional involvement with the woman he initially married only for convenience.