Benigno “Benny” Caldera knows an orphaned Boricua blacksmith in 1910s New York City can’t call himself an artist. But the ironwork tank he creates for famed Coney Island playground, Luna Park, astounds the eccentric sideshow proprietor who commissioned it. He invites Benny to join the show’s eclectic cast and share in their shocking secret: the tank will cage their newest exhibit, a live merman stolen from the salty banks of the East River.

More than a mythic marvel, Benny soon comes to know the merman Río as a kindred spirit, wise and more compassionate than any human he’s ever met. Despite their different worlds, what begins as a friendship of necessity deepens to love, leading Benny’s heart into uncharted waters where he can no longer ignore the agonizing truth of Río’s captivity—and his own.

Releasing Río could mean losing his found family, his new home, and his soulmate forever. Yet Benny’s courageous choice may just reveal a love strong enough to free them both.