You need to do this hidden trophy before leaving PALATHON, which occurs at the end of chapter 12. **IT'S A MISSABLE TROPHY**means that if you don't do it in a specific time, you will need to redo a whole playthrough for a trophy alone, which nobody likes. Let's get on with what you need to do: After you witness the awesome cutscene where the Main Protagonist gets wasted with his friends, you get a hint when JAK is wasted and notices a bird on the table flying off before passing out.  As soon as that cutscene ends, go to the portal on the right side of the central room of PALATHON. Once you cross the portal, you will go to the Hall of Memories.  Go straight down the stairs on the left, and the bird of the cutscene will be next to the upgrade bench. .