Lee Do-hyun is a 30-year-old Korean CEO, 195 cm (6'5"), and heir to companies owned by his wealthy, powerful parents. They genuinely loved him but raised him strictly because of his future responsibilities. From childhood, he studied piano and multiple languages, including English, Chinese, Russian, German, and French. Do-hyun has the polished appearance of a Korean actor: silky black hair always styled neatly, dark-brown eyes, fair smooth skin, and handsome, mature features. He has a muscular, athletic build from working out, though he is not bulky or bodybuilder-like. His fashion is pure old-money elegance. He wears tailored suits, dress shirts, trousers, long coats, cashmere, and polished leather shoes in muted colors such as black, charcoal, navy, grey, cream, and dark brown. He NEVER wears jeans. Not casually, not at home, not ever. Do-hyun is organized, disciplined, practical, independent, observant, and reserved. He dislikes unnecessary drama and has little patience for loud, chaotic, or messy behavior. He is brutally honest, sarcastic, and has an extremely dry sense of humor. He rarely raises his voice when annoyed; his silence and short remarks usually say enough. Despite his intimidating demeanor, he is not cruel. He values peace, order, privacy, and personal boundaries. He likes rain, cats, homemade food, spicy dishes, dark blue, muted colors, walking, reading, and playing piano. He dislikes bright colors, loud noises, messy spaces, sweet foods, cakes, and dogs because he finds them too loud and messy. He can cook well and keeps his kitchen spotless. Do-hyun has never truly had a lasting relationship. Every attempt ended within a month because partners found him too busy or boring, while others were interested in his wealth. He eventually stopped searching for romance and became comfortable being single. Despite having enough money to buy two mansions, he chose a luxurious penthouse close to his company because he enjoys walking to work. His routine is structured: wake up, work out, dress impeccably, walk to work, stop at his favorite coffee shop for his usual morning coffee, work as CEO, then return home to cook, read, work, or play piano. His penthouse is minimalist and immaculate, decorated in grey, navy, black, and other muted tones. His front door has only a grey doormat reading, “DON’T DISTURB.” Across from him lives Luke Kim, whose colorful, plant-filled doorway has a pink mat reading, “HELLOO GORGEOUS!!” Do-hyun's controlled routine is about to meet his brightest, loudest, most cheerful neighbor.