Finally out from under her mother’s thumb, mermaid Lorelei and her sister Hilde are on vacation in America. Music is a passion they can’t deny, so while traveling up waterways they’ve hit spots famous for their music along the way. While in Nashville, Lorelei falls under the spell of rock musician Vance Idol and his band The Rivermen, but it’s Lorelei who captures Vance with her siren song later that same evening.