Following the previous episode, with Layla being unsuccessful to rescue the Pixies, the Winx come to her aide. This is also the first time we meet the Trix in the new season, as they're being held as "guests" in the positive realm where they can't escape the goodness of the world. And boy, does it drive them insane. Of course, not until Lord Darkar breaks in and takes the witches with him.
It would have been nice to have this episode and the first of Season 2 air back-to-back. They did air double episodes later in the season after all.