The Secret World of Og is a children's adventure about three young girls who venture into an underground cavern beneath their playhouse to look for their lost baby brother. There, they discover a land of little green people who are enamored by the world above but won't allow anyone to leave their cavern for fear they might "tell".

Yogi escapes from Jellystone and hides out in a department store - posing as the Store's Santa. Along the way, he helps a little girl to rediscover her faith in Christmas.