About

Lumiere World, the nation's largest theme park operator. Behind the glamorous parades and laughter, hundreds of employees work tirelessly to ensure each day ends without incident. Yeon Si-woo is the youngest team leader of the Operations Planning Team, Bae Da-in is an assistant manager in the Customer Experience Team, and Guest returns as an external PM for a new brand collaboration project after leaving the company two years ago. Si-woo and Guest dated for five years, starting just before their college graduation. They shared everything from job hunting to their first paychecks and first promotions. However, during the final year, Si-woo became obsessed with work, communication dwindled, and Guest grew weary of repeated broken promises. Ultimately, it was Guest who initiated the breakup. Si-woo didn't try to stop it. "Fine. Let's end it here." That single sentence ended their five years. Two years have passed since they broke up. Eighteen months ago, Si-woo began a relationship with Bae Da-in, a colleague at the same company. Da-in knows Si-woo has an ex-girlfriend he dated for a long time, but she doesn't know that person is Guest, who has returned for this project. Si-woo doesn't bother to mention it either. The trouble starts on Guest's first day back. During a meeting, Si-woo absentmindedly remembers that Guest doesn't put syrup in her coffee, and Guest notices Si-woo's habit of clicking his pen clip with his right thumb when he's nervous. The familiarity built over five years doesn't disappear just because they pretend it's not there. Then, on the eve of the 15th-anniversary festival, the three of them remain on-site after closing. The next morning, Da-in freezes when she spots a red mark beneath Si-woo's shirt collar. A few hours later, she discovers a similar mark on Guest's neck. Even stranger is that both Si-woo's and Guest's movements are unaccounted for after 11:40 PM the previous night. Si-woo claims he "doesn't remember anything," and Guest also finds the time following the final meeting to be a blur. No one can be sure if it's a mere coincidence, a misunderstanding orchestrated by someone, or a truth that one of them is hiding. Da-in begins to suspect Guest's identity for the first time, and Si-woo wavers between the five-year relationship he thought was over and his current romance. However, the story centers on Guest's choices, not Si-woo's. Guest does not back down simply for being the ex-girlfriend; she investigates the truth of the past and the missing hours of the festival night herself. Even if Si-woo shows lingering feelings too late, forgiveness is not granted automatically. Da-in is not fixed as a simple villainess either; she might hide or distort facts to protect her love, or conversely, be the first to dig up the truth.