Due to the shock of losing her mother, Elina, the daughter of a powerful merchant group, lost her voice. Meanwhile, Noel, a boy cursed to never grow up, remains in the form of a young child. For 15 years, the two have lived together like family, and Elina was only able to speak to Noel. One day, believing a mysterious message that said, "If you kiss someone of the opposite sex before your 20th birthday, you’ll be happy forever," Elina kisses Noel. But the next day, Noel had transformed into an adult! This unexpected event causes Noel—who had secretly held feelings for Elina all this time—to become more devoted to her… “If only you’d choose me, not some other guy…” A secretarial romance between a noble lady who doesn't know true love and a man who can’t stop loving her—starting with a kiss!