If Lorelei sings, someone will die.
Lorelei craves song as much as she needs the water. Both sustain her and fuel her mermaid powers.
But her mother has cursed her voice, and if Lorelei sings long enough, any mortal man within earshot will die.
Rockstar Vance Idol has been courting death for a while. He believes he killed his girlfriend. He can't shake his alcoholism, and his attempts are ruining the music career he and his band have worked years to build.
Lorelei sang. Vance nearly died. Now, Lorelei has to make amends to the human with a death wish, without falling in love with him and losing her own immortality.