To begin the 24. A Simple Request side quest in Trinity Trigger, speak with the Loving Wife on the western side of Festibane. For this quest, she’ll need you to travel to Festibane Trail: West to look for 3 Sunsetters. They can be found in shiny bushes around the area.
See the below map for their exact locations!
Once you’ve collected all 3, return to the Loving Wife to complete the quest. As a reward, you’ll receive Defense Augite IV and Purification Bell x3.