Merfolk's Lullaby

(Something is carved here. You're not sure how, but you can understand its meaning...)

That moonless night you broached the waves and spoke of us so graciously. I curse them in their wretched graves for luring you with treachery. They bound you, chained you, gentle King, for callously they had in mind. To hold you there, and so to bring a final end to Siren-kind.