Pyper's plan to make a glowing tree has backfired, so he asks you to bring him 10 Sunset Fireflies instead.
Quest Location
Talk to Pyper near Highland Stable, at 0529, -3394, 0057, to start the quest.
How to Complete the Quest
Beedle at Highland Stable sells Sunset Fireflies, but he only sells three at a time. If you go north, you might find Eryck riding his wagon. He sells five Sunset Fireflies at a time. You can keep going north on this road, and if there is a camp next to the tree, you can find more Sunset Fireflies there.
When you have enough, talk to Pyper. He asks you to bring Haite to him at night. She is at the nearby stable, so go into the tent at night and talk to her there. She will follow you, so go out of the tent, make sure she doesn't fall too far behind, and go to the tree where you talked to Pyper earlier. When you have reached the correct location, there will be a cutscene.
Quest Reward
Afterward, Pyper gives you a Big Hearty Truffle.