The podcast episodes explore various mysteries and unknowns surrounding the cosmos, including the enigmatic nature of black holes and the ominous 'Hole in the Sea' that represents the unknown.

These unknowns serve as the driving force behind the narratives, building suspense and curiosity as the characters and listeners seek to unravel the mysteries of the universe.

The topic of 'Mysteries and unknowns' is a central theme that connects the diverse range of podcast episodes, each delving into different aspects of the unknown and the human desire to understand the secrets of the cosmos.