Kim Yujin thought she left her high school rival behind-until she walked into her new job and found Park Sunghoon sitting at the top. Now the cold, brilliant CEO. She's here to win. He's not ready to let her forget the past. Old sparks. New rules. Rivals again... or something more?

The prestigious Blackthorne Academy hides many secrets, but none as haunting as the music that echoes through its abandoned conservatory at night. Rumor says if you follow the sound, you'll meet the boy who plays the Devil's Sonata-and you'll never be the same again. Yuri thought it was just a myth... until she heard it. Drawn by a melody too beautiful to be human, she finds him: Heeseung. Charismatic, cold, and too perfect to be real. There's something in his eyes that promises both salvation and destruction. He tells her he's cursed. That every note he plays feeds the darkness that's consuming him-and now, it's tied to her. Yuri is the only one who can either save him... or end him.

A bold, rich girl Kim Serin who wants to be a independent women lands an interview at Korea's biggest company, Sim Co. Jake sim, not just her boss- he's the CEO of Sim Industries, a billion-dollar tech empire-and he picked Kim Serin as his personal assistant. She finds him hiding something and wants to find it? Was he mafia? What was he hiding? Or just her imagination? Started: 07/05/2025 Ended: ?

At school, Yang Jungwon is the cold, silent, insanely handsome boy no one dares approach - poor, mysterious, and hiding a family life no one knows about. He keeps his distance, even though he's part of the heartthrob friend group that every girl dreams of. Hwang Haeun is the opposite: clumsy, rich, funny, a little shy, but popular thanks to her stunning looks and sharp mind. She's got everything - or so people think. Their worlds shouldn't cross... until one unexpected moment sparks a connection that neither of them can ignore. Behind Jungwon's icy walls and Haeun's perfect image, they discover they're both hiding more than anyone could guess.

Lee Ahyeon and Park Sunghoon were forced into a high-profile arranged marriage - not for love, but to merge two powerful companies. She's sweet, delicate, and painfully kind. He's cold, calculating, and sees her as nothing more than a business deal. They don't know each other. They don't like each other. And behind closed doors, their marriage is nothing like the fairytale the world sees. But the longer they live together, the more the tension grows - sharp words, lingering glances, and stolen touches. Because under all that ice... something is starting to burn.

──── 𝗙𝗢𝗥𝗘𝗦𝗛𝗔𝗗𝗢𝗪 ✸ IN WHICH . . . a grumpy girl tired of living meets a sunshine boy who's life is just beginning. ﹙ martin edwards park x fem!oc ﹚ ﹙ grumpy x sunshine au ﹚ ongoing. | 2026