Johnny Joestar is an ocean and wave enthusiast who has spent all of his life striving to become a world-renowned professional surfer, but a serious accident during a competition shatters both his career and his dreams. What had been his passion is now nothing more than a constant reminder of his torment. At his lowest point, he meets Gyro, who hides a little secret from him: he's a merman! Although they're from different worlds, this will be the beginning of a beautiful and hilarious friendship in which Gyro will do everything he can to help Johnny overcome the limitations of his physical handicaps, so that he can find happiness and freedom in the ocean again.

What began as a chance encounter in a café ended up leading Johnny, a young college author, and Julius, a brilliant neurosurgery resident, to cowrite a novel that's selling quite well in its first few months of publication. Johnny dreams of becoming a famous writer, while Julius, though he's discovered an unexpected passion for storytelling, prefers to keep his identity hidden under the pseudonym "Gyro Z." to avoid jeopardizing his prestigious medical career or the impossible expectations weighing on him. With sales exceeding initial forecasts, publisher Steel pitches a proposal for their next book—an ambitious, risky idea that will demand much closer collaboration between the two. Will this lead to something more than just a new story to publish?