The Key to Love

Location
Find Charlie in a cave near Taylor's Farm.

You must first have completed the quest Erma's Love Shrine.

Chat With Charlie

 * 1) Head toward the shipwreck at Taylor's Farm and search for Charlie. You can find his corpse hidden in a cave near some boars.
 * 2) Read Charlie's Journal to learn about his fate, and the fate of the key.

Shipwreck Salvage

 * 1) After reading Charlie's Journal, head to Ramshackle Reef.
 * 2) Search underwater near the sunken ships, until you spot a key on a rock just below the surface. Retrieve.
 * When you are in the vicinity of the key, the journal will update.

Pop The Trunk!

 * 1) Return to Taylor's Farm and dive into the cabin of the sunken ship.
 * 2) Open Erma's chest to retrieve.
 * 3) Return the bracelet Erma to complete the quest.