A brief description of the manga Dragon Ball Chou (Super):
In some years after the fight against Majin Buu, Son Goku lives secluded in the country together with his family. Since the earth is no longer threatened by evil forces, Goku is no longer in top form because he lacks training.
But suddenly a force appears on earth that he doesn’t know. Beerus, the god of destruction, has descended to earth, Through a prophetic dream, he has seen the Super Saiyajin God and now wants to fight against him. But who should this ominous Saiyajin God be?