Curses: Bubbles overhears a bad word from the Professor. Then her sisters start to use it, too, and cause a shocking reaction around Townsville. When a giant potty mouth monster comes to attack, the Professor tells the girls what the “word” means and the girls teach the potty mouth a lesson.

City of Frownsville: A miserable scientist named Lou Gubrious uses his machine to switch everyone’s happiness with his crying depression, making him the happiest man in Townsville. The girls has to find a way to make to make the people of Townsville happy again before they drown in their sorrow.

Supper Villain: The Powerpuff Girls’ new next door neighbors, the Smiths, seem very nice and average—until the father Harold Smith reveals his ill-fated aspiration of becoming a super villain, and takes Professor hostage.

Three Girls and a Monster: An undefeatable monster comes to Townsville, with Blossom (using team tactics) and Buttercup (using direct action) disagreeing on how to defeat the monster. On the other hand, Bubbles uses her “sugar” personality, by asking the monster to leave, which surprisingly ends up working well.