S4·E17 The Enchanted Island

The Winx girls travel to the island from a vision of Roxy's, the mystical world of Tir Nan Og sealed within the White Circle. Upon arriving, a mysterious figure keeps calling out to Roxy and a dark force soon abducts the Winx, taking them to the prison of all Earth's fairies. After freeing the Earth fairies, they reveal that they want revenge against the humans who imprisoned them, and declare war against all of humanity in turn.