Now You See It – Now You Don't
The crew are asked by Wahnee to investigate a planet that has disappeared – and they find one actually has

Changes
The son of Net, book five, decides to become a sorcerer. He is a decent person and this is the story of the time he was a young man until his old age.

Gothic World
Maita wants to make some overhauls and changes so Z goes to a world in a pre-industrial stage for a vacation.
As one would expect, it's a working vacation. There is something very wrong on this world – something that could prove disastrous in a century or so.

Vacations Don't Always Work Out
A vacation on Tlorg results in the discovery of a scheme that could destroy the universe? Kurk joins the crew.

Us Barbarians
Z gets to be a barbarian when he, Kurk, and Thing (and later, the golems) go to a world to try to find why it is so cyclical for disaster.