This achievement is unlocked by replaying the Very First Mission of Episode 1
"An Encounter with Xion"
The reason of this is because you're helping Alma recap the events of Episode 1-3
So simply head to the quest counter or talk to Xiera on the Bridge and select Episode 1
If you don't see the mission, at the top of the Window change "Quest Not Cleared" and switch it to "All"
It's just a cutscene so you can load up and skip. Achievement unlocked