In the era of cavemen, a boy with white skin is born on the night of a storm. He is immediately outcast as a cursed child, doomed to bring disaster to whoever he comes across. This boy is set to be sacrificed to the Dragon King (a tyrannosaurus), but is saved by an ape woman, Kitty, and is given the name Ryu.

Ryu grows up as her child, and soon encounters the world of the cavemen again - with Kitty dying in a skirmish between them and the Dragon King. Ryu soon learns that Kitty is not his birth mother, though she is somewhere out in the world. Faced with this mystery, Ryu ventures on a journey to seek her - all while dealing with discrimination from other cavemen, and the ever-present danger of the prehistoric era.

The first part of the Ryu Trilogy.