Lost Earrings is the first quest given by Alchemist Synthia.
Before: How could this happen? I walked through the Tunebro Forest yesterday, and I lost my earring! Could you please go and take a look?
During: My precious earrings!
Bring back Synthia's earrings.
Note - the earrings are in the background during the 3rd wave of enemies. Click on the little blue dot.