|"The Secret Guardians"|
| Season 13, Episode 7B|
|Original Airdate:||April 6, 2010|
|Written by:||Guy Lancaster|
|Storyboard by:||Daniel Decelles|
"The Portrait of the Artist as a Young Tibble"
"Fernlets by Fern"
Arthur, Binky, and Sue Ellen find a woodland oasis near their homes and vow to keep the area a secret. Soon they start to find evidence of human habitation and wonder if they've discovered an ancient civilization.
Sue Ellen and Arthur go down to the brook to test a model boat that Sue Ellen made, they run into Binky and the trio launches the boat, but loose control of it and follow it down the river and stumbled into a paradise like enclave of the woods that they name arsubia and swear on a rock to keep it secret from the world.
For Arthur and Sue Ellen keeping arsubia a secret from the world is hard because Sue Ellen discovers a few arrow heads and suspects that a lost civilization occupied the area. Arthur finds it hard to keep arsubia a secret because he hates keeping secrets from Buster.
Binky takes it upon himself to enforce arsubia's secrecy, adopting a vigilante approach and requiring passports upon entrance. Eventually the trio stumble upon Buster, who informs them "arsubia" is actually "Baxteronia" a place Buster discovered with his dad since he was four.
The episode ends when a sudden rainstorm starts and Buster tells them to take shelter in a cave located in the enclave.
- The Episode and title are parodies of The Secret Garden