Winx Club (2004)

S2E4 Queen of Perfection

Stella and Brandon plunge into an underground river at the chasm's base, swept away by the current into a whirlpool that deposits them on the banks of a hidden realm known as Downland. There, they encounter a palace guard and a sentry named Sponsus, who leads them to Amentia, the meticulous queen of Downland. Mistaking Brandon for her long-lost husband, Amentia's obsession grows, leaving a heartbroken and weakened Stella desperate for sunlight to restore her powers. If she fails, her friends could fall prey to monstrous threats lurking nearby!