Obtained: Speak with Bulma in Capsule Corp. during post game with Trunks
Objective: See if Bulma can help find what you are looking for
Make your way to Capsule Corp. and speak with Bulma in the garden to ask her for help. Following the cutscene, travel to the North Mountain Area then head for the southwestern part of the map. Speak with Android 17 to start a battle with him. Defeat 17 to complete the story.