Ruby Zhang’s summer vacation in Maui starts off normal enough—until she meets a merman on the beach.

Back home in foggy San Francisco, Ruby’s days are filled with studying for AP exams, late-night band rehearsals, and laughter with her best friends—Grace and Tye, twins with big dreams; Mari, a passionate club leader; and Tomas, a quiet musician. Together, they are preparing to debut their first original song at the end-of-year variety show. Yet beneath the surface of ordinary high school days and shared dreams, each friend harbors private fears and quiet hopes: the pressure to be perfect, the ache of family expectations, the longing for something—or someone—just out of reach.

When Ruby misses the show as her family drags her to Hawaii for her dad’s business trip, Ruby’s dismay quickly fades when she meets someone impossible: a merman beneath the waves.

A gentle coming-of-age story about music, friendship, and the secrets we keep, The Secret Beneath The Crystal Surface follows five friends as they finish their junior year of high school and into summer.