Return to Pentalous is the 26th Proposed Serial in Spectral Shadows. It is preceded by Serial 25 - Quest for the Stairway to Heaven and succeeded by Serial 27 - The Valley of the Tauran Bears. It is currently not being worked on, meaning that the only available material is the summary on the Synopsis Page.
The summary is as follows:
Once again Pentalous is in serious trouble. Anthrodroids under the control of The Black Knight and The Astral Pirates invade. Shane is forced to play a game with The Black Knight for the survival of himself and the entire planet.
Meanwhile, Jon and Captain Harry use the game as a diversion and slip away to secretly evacuate the Pentalians. Captain Harry gets away with the equines, but it is up to Jon to save the male half of the species.