In the upcoming episode titled "Puffdora's Box," of Cartoon Network's "The Powerpuff Girls" Season 1 episode 14, it seems that while cleaning the house, Blossom will mistakenly open a mysterious box that will unleash several monsters into the world.
CLICK HERE to watch how Blossom will tackle with the situation and how Bubbles and Buttercup will help her put the monsters back into the box.
According to the synopsis of the episode by the Powerpuff Girls Wikia, "While cleaning up the house, Blossom accidentally releases a group of party-loving ghosts from a 3,000-year-old box."
The professor will tell the girls to clean up the house and stock all the things in piles. After he leaves, Bubbles and Buttercup will decide to make two piles of stuff, labelling them as "keep" and "toss."
However, given her leadership traits, Blossom will object to the method and tells them about her exhaustive plan of making several piles instead of just two. Reluctant at first, Bubbles and Buttercup will decide to do it Blossom's way.
Bubbles will realise soon that the work is getting more hectic and have a nervous breakdown. Buttercup will tells Blossom they won't be able to work this way. When Blossom will not listen, Buttercup will leave with Bubbles and Blossom will decide angrily to do the work all by herself.
However, while stocking the piles, Blossom will mistakenly open a box from the professor's laboratory. As a result, several monsters will make their way into the house and tell Blossom they will conquer the world the next day after partying hard.
Unable to comprehend them, Blossom will unintentionally summons Hope, a girl who knew how to send the monsters back. However, Blossom will not be able to convince her for telling her about the solution.
Therefore, Blossom will be left with no option other than to ask Bubbles and Buttercup for help to send the monsters back. Whether she will be able to do it will be revealed in the episode.