Series Nine is one of the Related Worlds and is the first one Christopher Chant visited in the company of Tacroy, Ralph's hired Traveller, who is also employed by Gabriel de Witt. The one world in Series Nine visited by Christophere and Tacroy is very warm, as in Tropical plus, and has a great many mushrooms growing everywhere on nearly everything. According to the narrative of The Lives of Christopher Chant, Ralph Argent, Christopher's smuggling uncle, carried on a great deal of his business among the worlds of Series Nine.

The Related Worlds
Series One, Series Two, Series Three, Series Four, Series Five, Series Six, Series Seven, Series Eight, Series Nine, Series Ten, Series Eleven, Series Twelve