Obtained: Speak with Master Shen at Orange City in the Southeast Mountains Area during the main story Fleeting Normality (as Gohan)
Objective: Defeat all enemies
Travel to Orange City in the Southeast Mountains Area then head east of the city to located Master Shen. Speak with him to trigger a cutscene that will lead to a battle with 3 Tao Pai Pai Machines. Defeat them to complete the story.