On this page of the solution comprehensive dedicated to Dragon Ball Z Kakarot, find out how to complete thesub story That good old Son Goku!.
Episode: Saga Buu - Episode 8
Period: "The End"
As Son Goku, go see Bora in the western forest area (pictures1and2).
Then go to Capsule Corporation and talk with Bulma (pictures3and4).
After the scene, you find yourself in the Central Plains area. Follow the marker to find the thieves and defeat the robots (pictures5,6and7).
Then follow the new marker and pick up the medicinal moss (pictures8and9).
The side story then ends and you get Bora and Upa's Soul Emblems.