Kat sees a young boy moping over an old photograph his late grandfather left him. Kat decides to take the boy to visit the location in the photo, treating the adventure like a treasure hunt. The boy reminisces about the times his grandfather used to take him when he was still alive, before he asks Kat to take him to the factory at the edge of town.
After Kat snaps another picture matching the boy's, he asks her to search for tree that matches the one in another photo his grandfather left him. During the trip, he remembers when his grandfather would sneak him out to see him, until his parents stopped it; this being the last time they saw each other before he died.
Eventually, they find the area described in the photo, only to find a Grigo station in its place. They learn that the tree was cut down sometime between the two games. Kat is disappointed that there's no treasure, but the boy remembers that the real treasure is the memories he had with his grandfather, and one important lesson: to focus on school, study hard, and make something of his life.
All you need to do in this mission is to escort the boy around Auldnoir snapping updated photos of the ones the boy has in his possession. The first is just below where you meet the boy; simply jump over the wall in front of you and free fall into the small park below, and snap a picture of the swing and the stairs behind it.
After that, head over to the factory, and get the bridge and Vendecentre in frame to match the second photo the boy shows you. Finally, the both of you need to find an old tree near the Fountain Plaza with an angle that catches the World Pillar in shot; well, the Grigo Station that now stands in place of the tree in question. The boy will tell you where is place is if you're stuck.