You'll have to make your way over to the Flower Shop in order to progress the story. Once inside, you'll automatically have a conversation with Eleanor. You'll finish the conversation with Eleanor looking visibly troubled. Once you've gotten control of Alex, there will be a blue shelf/chest of drawers/cabinets-thing with the left cabinet door open. Look down and you'll see the red shirt you need to interact with. Hold "LT" and then the "A" button, listen to the memory play out and the achievement will pop!