5-ji kara Heroine

Sayaka Mizukoshi is an office lady working at Five Star Pharmaceuticals, a major medical company. Since graduating college, she'd remained single to focus solely on her career, yet she never once regretted it. Because she can stay by the side of the company's handsome and capable president, Shinya Godai, serving as his personal secretary. Working alongside the man she admired and respected beyond romantic feelings… that was her happiness. But that happiness suddenly crumbled one hungover morning… A splitting headache from drinking too much, a warm hand touching her… completely naked body!? Peering at the the man sleeping beside her, it's unmistakably the president's face!! Mizukoshi panicked, but as she felt the lingering traces of last night's events on her body, she thought. "I'm probably going to be late for work today…" And so begins the romantic torment of a president's secretary, all stemming from one night's mistake! (Source: Akita Shoten, translated)