The world of Dying Light 2 is cruel and people frequently take advantage of each other for resources. One of the side quests you can get in the game is called Sentimental Value. This side quest focuses on a child called Maya and her affair with the bandits.
To start the Sentimental Value side quest, go to the southwestern part of the Horseshoe region. Here, you will find a child called Maya on a rooftop, taking shelter from the sun. Talk to Maya to start the quest and she will tell you about the bandits.
You have to fight and defeat the 3 bandits that will appear and report back to Maya.
She will tell you about her stolen music box and the music it plays. Now wait for nighttime like Maya says and head to the quest area.
When you go inside the building, you will encounter some infected. Take them out if you need to and go inside the elevator on your right. Jump up the elevator and use the metal bars on your right to get to the upper floor.
Enter the exit with wooden planks and be prepared to kill the infected that swallowed the music box. To do this, you can jump across the room to the other side, and you will find a gas tank. Ignite it and throw it on the infected.
Jump across the platforms until you reach the platform with a door and a throwing spear. Use the throwing spear to deal some extra damage. Jump down and take care of the smaller infected first.
NOTE: The infected is slow but has a wider range of attacks. Be sure to step back when it swings its arms.
Once defeated, search for the music box in its body to complete the quest.