The Isle of Nerissa

On the sea charts it is no more than a nameless rock, but every ship that sails too close vanishes. Survivors who wash ashore are few, and they speak only of a song. You sail aboard a ship that must force the passage, for beyond the island lies the only route to the besieged port city, and the captain has no choice.

The island looks like a paradise of white sand and green palms, until the song begins. The sirens sing so bewitchingly that sailors leap overboard to come closer, and drown themselves with a smile. Whoever washes ashore alive slowly becomes part of the choir, singing forever to lure the next ship. The rocks all around lie strewn with wrecks and bleached bones.

You arm yourselves against the song with wax, chains, and pure willpower, navigate between the rocks without steering yourselves onto the reefs, and go ashore to find the source, for the song has a heart: Nerissa, the Eldest Voice, whose voice directs the others. Along the way you meet the half-transformed victims of earlier ships, caught between human and choir.

The turn: the spell is no curse but a pact, the sirens were once drowned sailors themselves, bound to the island until they have gathered enough souls to go free. In the climax, on the singing rocks with the song thundering in your skull, you must silence Nerissa and break the pact, or become the newest voices yourselves in a choir that never ends.