One dark night, at water's edge, a family of musicians encounter aquatic sirens Silver and Golden. After assuring the family that they won't eat them up, the winsome sirens are recruited to join the Figs and Dates band at a neon-lit Warsaw dance club. When Silver becomes romantically entangled with beautiful blonde bassist Mietek, the more cunning Golden, who cannot escape her bloodthirsty nature, worries that her sister's relationship will doom their shared dream of swimming to a new life in America.