Sota Yukimura (Hokuto Matsumura) works in the General Affairs Department of "Nose Cosmetics." He is an unassuming, harmless man who keeps a low profile—the type who blends into the background. Shy and lacking presence since childhood, he has led an ordinary life with nothing to boast about. That is, except for one thing: he has harbored an unrequited love for his first crush for twenty-five years. In stark contrast to Sota, Mariko Nose (Sae Okazaki)—the daughter of the company president and head of the Second Brand Division—has lived a dazzling, charmed life. She spearheaded the cosmetics brand "Velel," turning it into a massive success. While many employees view her with a cynical eye, dismissing her achievements as mere nepotism, she shares a close, candid bond with only one person: her secretary and single mother, Izumi Takeda (Nozomi Sasaki). For a rank-and-file employee like Sota, Mariko—an executive of the same age—is someone far out of his league. He has never even spoken to her, and she is completely unaware of his existence; yet, when he tries to help her out of a bind at a café, she responds with a distant, cold attitude. However, the two had actually met once before, triggered by an incident during their childhood... For the twenty-five years since, Sota has quietly watched over Mariko's life. He had always been content simply observing her from afar—or so he thought. Mariko, aiming to launch a new skincare line for "Velel," is told by her father—company president Ginjiro Nose (Ken Ishiguro)—that she needs to rework her proposal. Seeing her in distress, Sota breaks his silence for the first time and speaks to her. From that day on, Sota's pure love begins to spiral into madness. Meanwhile, mysterious incidents start occurring around Mariko. Her ordinary daily life is turned upside down as events take a thrilling, dangerous turn.

Sota Yukimura (Hokuto Matsumura) works in the secondary brand division of the cosmetics company "Nose Cosmetics." For 25 years, he has harbored an unwavering, unrequited love for his boss—and first love—Mariko Nose (Sae Okazaki). Sota, who would brave any danger for Mariko's happiness and constantly rescues her from trouble from the shadows, suddenly finds himself a murder suspect. Just before Tsuyoshi Tateiwa (Tomomi Maruyama)—an executive who had been at odds with Mariko—was killed, security camera footage near the scene captured Sota's image. Questioned by Detective Taisuke Sakura (Tetsuji Tamayama) of the First Investigation Division, Sota admits to meeting Tateiwa shortly before the incident but denies the murder... Meanwhile, completely unaware that suspicion has fallen upon him, Mariko feels gloomy as her birthday approaches. It is a Nose family tradition to hold a gathering at the family home every year for her birthday, yet Mariko detests these parties... She adamantly refuses to communicate with her father—company president Ginjiro Nose (Ken Ishiguro)—about anything other than work. What exactly is the root cause of this rift? Wanting to see Mariko smile, Sota concocts a work-related excuse to visit the Nose residence, attempting to infiltrate the birthday party to discover why she dislikes the occasion... What dark secrets of the Nose family await him?