Shiranai Kanojo

College sweethearts Riku and Minami marry. He becomes a novelist while her singing dreams fade. After a fight, she vanishes. Suddenly, he's just an editor, and a singer named Minami Maezono exists-but he's never met her. Riku is a successful author who marries Minami, but their relationship deteriorates after he throws away words of encouragement for her. The next morning, he wakes up to find himself as a young editor at a publishing company instead, with no memory of his previous life as a novelist. As he navigates this new reality, Riku discovers that the woman he loved has become a famous singer, Minami Maezono, but they've never met.