In this fantasy adventure, four children — Penny, the leader; Pamela, her common-sense sister; Peter, whose life's ambition is to become a garbageman; and Patsy, who collects frogs in her pockets — set out in search of their baby brother, Paul, better known as “The Pollywog,” who has vanished mysteriously from their playhouse.

[1] The TV series extends the storyline of the original book, following the five Berton siblings as they descend through a hole in the floor of their playhouse to explore the underground world of Og.

There, amid subterranean rivers, caverns and elaborate villages built of mushrooms, they interact with little green creatures called Ogs, and their myriad neighbours - trolls, ogres and fairies, and a mysterious sea monster named Nessie.

Carousel Theatre produced a stage version of The Secret World of Og in April 2009 in Vancouver, BC, adapted by Governor General's Award winning playwright Kevin Kerr.

The Secret World of Og, with libretto and music by Dean Burry, is directed by Joel Ivany and conducted by Ann Cooper Gay.