Sota Yukimura (Hokuto Matsumura), an employee at the cosmetics firm "Nose Cosmetics," has harbored a secret crush on his first love, Mariko Nose (Sae Okazaki)—now a department manager at the company—for 25 years. He successfully engineers a transfer to her division by feigning coincidence. Driven by a desire to be of help to her, he gathers evidence of expense fraud committed by executive Tsuyoshi Tateiwa, who harbors jealousy toward Mariko and seeks to sabotage her. Sota attempts to confront Tateiwa directly using this leverage but fails to achieve his goal. Shortly thereafter, Tateiwa's body is discovered; bearing multiple stab wounds, the case is treated as a homicide, and the police launch an investigation. The next morning, Taisuke Sakura (Tetsuji Tamayama), a detective from the Metropolitan Police Department's First Investigation Division, arrives at the Nose Cosmetics office. While the company is thrown into turmoil by the news of the murder, Mariko is left speechless upon seeing Taisuke. He was the man she had been forced to meet for a matchmaking date just recently by her grandmother, Akiko Nose (Mitsuko Oka). Although there had been no contact since that meeting, Mariko—unaware that Taisuke was a detective—is stunned by this unexpected reunion. Taisuke interviews the company president, Ginjiro Nose (Ken Ishiguro), suspecting that the person who sent evidence of Tateiwa's fraud to Ginjiro on the day of the incident might be the killer. Meanwhile, Sota, quietly savoring the joy of working alongside Mariko, joins her for a round of golf intended to entertain a department store president. He is overjoyed as he grows closer to Mariko, but this happy moment takes a sudden turn when he discovers a shocking truth hidden within the attempted kidnapping of Mariko that occurred 25 years ago.

Sota Yukimura (Hokuto Matsumura) works in the brand division of the cosmetics company "Nose Cosmetics" and has harbored an unwavering, unrequited love for his boss—and first love—Mariko Nose (Sae Okazaki) for 25 years. Unaware of Sota's feelings, Mariko finds herself unexpectedly weeping in his arms, reminded of her beloved late mother. She begins to take increasing notice of Sota, who always appears to lend a hand whenever she is in trouble. As the police begin to eye Sota as a murder suspect, he remains determined to protect Mariko's smile and continues to investigate the truth behind the attempted kidnapping she suffered 25 years ago—an event that left her deeply traumatized. Sota discovers a connection between the serial kidnapper who attacked Mariko, Satoru Hatano (Yoji Tanaka), and her father, Ginjiro Nose (Ken Ishiguro)—the president of Nose Cosmetics. Suspecting Ginjiro might have been involved in the incident, Sota attempts to uncover the president's secrets. Meanwhile, Ginjiro's secretary, Gota Asai (Atom Shukugawa), is suddenly replaced. When Mariko worries about Asai's abrupt disappearance from the office, Ginjiro dismisses it, claiming Asai is simply taking some time off... That night, Sota sneaks into the empty office and searches through Asai's desk, looking for clues to expose Ginjiro's secrets—but what he finds... What exactly has happened to the missing Asai? Furthermore, will Mariko finally discover Sota's long-held secret love...?