This is a children’s spec script. It’s a story with a moral message about being two-faced.
Peter, who has an over active imagination, overhears his mother “slagging-off” various friends in great detail. Descriptions that Peter takes quite literally. His imagination draws up images of monsters, pirates, and boogeymen etc, and he sets out to banish the beasts. He soon realises through several quests that they are not beasts at all, and in fact maybe it’s his own mother that is the ‘Incredibly grotesque monster with two disgusting faces’