The lovers sing their ecstasy. Meanwhile, a storm arises unobserved. The trumpet that should have been sounded by Hero is sounded from the vaults beneath the tower. Leandro throws himself back into the Hellespont while Ariofarno and his priests chide Hero for her neglect as they discover its cause. A thunderbolt shatters a portion of the tower, and Leandro's body is disclosed.
Hero falls dying to the ground, while the archon rages.