The Nextdoor Neighbor is a PTA Mom

One day, Fillyjonk moves into the Moomin Valley with her three children. Although the Moomins hold a welcome party with a lot of unique idea's meant to please them, Fillyjonk just dismisses them as harmful to the upbringing of her children, strictly prohibiting them from playing with Moomintroll and his company. Her children try to follow their mother's BEHAVE-YOURSELVES type of orders at first, but their natural instinct as children gradually draws them into Moomintroll's circle of playmates.