This quest requires you to interact with a dead drop in Weeping Woods.

If you go to Weeping Woods you will find tree stumps with locks on the top that you will be able to interact with. You only need to interact with one of these to complete this quest and there are 5 dead drops in Weeping Woods.

Here is a map showing the locations of all the dead drops if you are having trouble finding one.

Map credit to fortnite.gg