[1] Protagonist Arthur ("Art") Mumby and his older sister Myrtle are invited to the Starcross hotel on a small and periodically barren asteroid.

There, Arthur's mother Emily suspects that Starcross is built on a piece of Mars which routinely slips through a hole in the fabric of time, and Myrtle then discovers that Sir Richard Burton and his Martian wife Ulla have been changed into trees.

In the following night they are attacked by the Moobs, a species with the ability to shapeshift into forms of inanimate objects, which currently resemble animated black top hats, which take control of Jack's crew and other guests, including Emily.

Art frees Jack's crew from their influence, and they return to Starcross to discover that Arthur's mother, having sufficient memory to sate them, has subdued the Moobs.

Thereafter Myrtle, challenged by Jack, determines to study the cold fusion used in space travel; whereas Professor Ferny, a plant-like creature, promises to find a cure for Sir Richard and Ulla's transformation.