The show features three small clay monsters, the Plonsters. They are Plif (the green plonster), who likes to do practical jokes, Plops (the blue plonster) who is the cranky one and Plummy (the orange plonster) who is the cheerful one. They can morph themselves into anything, and their language is some kind of gibberish. The plot of the show is usually that Plif and Plops bully Plummy by ruining everything he does (as well as excluding him from some activities whenever possible), but he gets back at them every time, and every episode ends with the three of them playing together peacefully.