Morningside Opera continues its world-premiere staging of composer-soprano Kate Soper's brilliantly quirky new theatrical piece: part play, part chamber opera and all scholarly beguilement. Spinning her saga from contrasting myths and theories about sirens, Soper sings with Brett Umlauf and Gelsey Bell in a cohesive mix of stark chant, modernist discord and pop-tune flourishes. All three share a piano that doubles as a drum and an echo chamber in Rick Burkhardt's imaginative staging.