Nobody's Home is a hidden achievement/trophy in Metro: Last Light, awarded to the player if they ignore the ringing phone located in the River of Fate. The phone is part of the story during the Khan level. If you follow Khan, you cannot miss it as a light above it turns on when it rings and Khan mentions it. It can be missed by picking up the phone. If you want the achievement/trophy but also want to answer the phone, ignore it and move on - you will get it upon reaching the end of the tunnel - then restart the checkpoint. You will be back before the phone and can answer it to hear the voice. Be careful not to go too far, or the game will autosave and you will have to replay the whole chapter to hear it. If you reached the area with Darkness, you have gone too far.