Robert La'Bassiere

An evil caliph offers his daughter’s hand in marriage to a prince if he can complete a perilous quest for a magical rose. Helped by a young boy and a magic carpet, Prince Hasan has to overcome genies, fire-breathing monsters, and treacherous swamps to reach his prize and claim the hand of the Princess Zuleira.

When the leading lady of a low-budget musical revue sprains her ankle, the assistant stage manager is forced to understudy and perform in her place.

The TARDIS arrives on the unnamed planet of the Gonds, who are ruled and taught in a form of self-perpetuating slavery by the alien Krotons — crystalline beings whose ship, the Dynatrope, crash-landed there thousands of years earlier after being damaged in a space battle. The Krotons are in suspended animation, in a crystalline slurry form, awaiting a time when they can be reconstituted by absorption of mental energy. Periodically, the two most brilliant Gond students are received into the Dynatrope, nominally to become "companions of the Krotons", but in truth to have their mental energy drained, after which they are killed.