On this page of the solution Dragon Ball Z Kakarot, discover the complete progress of theLonely Guardian sub story.
Episode: Saga Buu - Episode 8
Period: "The End"
To begin this side story, you must play Trunks from the future. To unlock this character, approach Bulma and Trunks in front of Capsule Corporation as Son Goku (pictures1and2).
Then enter Capsule Corporation as Trunks, and speak with Bulma (pictures3,4and5).
Then go to the North Mountains area and speak with Android 17 (pictures6and7). Finally defeat Android 17 to end this sub story and obtain Android 17's Soul Emblem (picture8).