The Frozen Palace (aka The Crown of Dreams)

Bloom and the other Winx girls are on Sparks looking for Bloom's dragonfire in the frozen palace. Then a huge yeti like monster with a hoard of fire crabs assaults the girls and the palace. The Red Fountain boys (minus one Riven) turn up and stop the fire crabs then the girls stop the yeti. It ends with all 8 of them in the boys craft, heading back to Alfea.