Five siblings named Penny, Pamela, Peter, Patsy, and Pollywog have one thing in common: They like to spend their free time getting lost in their imaginations.
One day, several items in their house mysteriously go missing and the kids' perplexed mother asks about their whereabouts. Then while the siblings play a game, the baby, Pollywog, and their pet cat, Earless, go missing too.
The remaining foursome and their dog, Yukie, discover that there's a trap door in their playhouse. The kids and Yukie believe that Pollywog, and Earless, were kidnapped through there. So they enter it as well and search for the two. But what they find, they never would've expected: