The invasion of Earth has begun. Lord Gorgo of Prehistoria has launched his asteroid storm of rock-ships, sending his warrior Menosaurs with a clear command – DESTROY ALL HUMANS!

Rex, Rion and Tarrock hyper-drive to Madagascar on their quest for Grandidierite. Attacked by unknown ancient forces, Rion is seriously injured and is left dying…

Forced to confront his half-droid, half-Menosaur powers, Rex will have to overcome one of the biggest losses of his life if he is to save the planet – and his best friend.