O18, the second edition of Opera Philadelphia’s annual season-opening festival, launches on September 20 – on the eve of World Alzheimer’s Day – with the world premiere of Sky on Swings. An unflinching yet uplifting exploration of Alzheimer’s disease from the creative team behind O17’s I Have No Stories to Tell You, the new chamber opera finds fleeting beauty in memory loss, pairing the music of Lembit Beecher with a profoundly sensitive libretto by young playwright Hannah Moscovitch.