Beyond a Steel Sky

After the introductory cutscene, your main character will be walking through the desert and come across a young girl looting a corpse. Head towards her and after some dialogue, she will run away.

Look at the birds (will be known in-game as Gang-Gang) and press , select "Inventory" and scroll down to "Pie" - select "Use". Now go over to the body and interact with it. After another cutscene which introduces you to Union City, you will unlock this achievement.