Jiwoo goes fishing with her father and snags a way bigger catch than she expected. The mermaid tangled in their net is injured, so they take her home and let her stay in their bathtub until she recovers. Meanwhile, the mermaid keeps flirting with Jiwoo, who hears a rumor that any human who betrays a mermaid's love will be cursed forever. Knowing this, Jiwoo feels anxious and can't get the annoyingly charming mermaid off her back fast enough. Or at least, that's what she keeps telling herself as she sinks deeper and deeper into a dangerous ocean...