Complex sentence: The Dazzlings intervene to ensure the Rainbooms' advancement to the final round despite their poor performance, and then beguile a jealous Trixie into trapping the band beneath the stage to take their place.
Split into simpler sentences: The Dazzlings intervene to ensure the Rainbooms' advancement to the final round despite their poor performance. Enraged, Trixie who traps the band beneath the stage to take their place.