The Travellers are hired by the ducal heir of Alekvadin to fly a safari ship first to Akussanja, to obtain specimens of a rare and wild species, and then to Tinea-Fabre where the animal is to be deposited into a wildlife preserve. After it has settled in, the young duke-to-be enlists the Travellers to hunt the elusive creature in its adopted habitat but it proves to be a wily prey with heretofore unknown abilities. The hunters become the hunted and are seemingly forced to fight off the entire animal kingdom of the preserve. They will end up in a pitched battle for their very survival.

Invasive Species includes:

• A complete adventure set in the Core
  
• The Superb Starling, a customised Type-K safari ship
  
• New and exciting animal encounters, including the sly and ferocious shakuurzarpi of Akussanja
  
• Maps of two wild alien worlds