Rex and Akan, having gained the power of the Dragon Stones, save Planet Dino from crisis once again. However, Cosmosaurus, who has collected all the Galaxy Stones, regains his body and executes a plan to plunge the universe into darkness. The White Dragon (Titanos), awakened from a long slumber, is the only hope to defeat Cosmosaurus. But Titanos, having lost his power, has shrunk in size and even lost his memory. The four scattered Dragon Stones that can restore Titanos's power must be collected!!! Cosmosaurus interferes with the collection of the Dragon Stones, and the Dino Hunter Kane is also after them. Rex and his friends begin their difficult adventure.