This is a walkthrough for the Treasure Hunt, The Missing Muse. Details on where to find Rosa.
A Yaran poet has left his poems scattered around the marina. They hint at his relationship with his missing lover, Rosa.
Head northwest of the town of Segunda until you reach the Pez Volador Diving Club, then interact with the note at the entrance to begin the quest. Now go over to the Bar y buceo Pez Volador Marina. then collect the Ambrosio’s Key from the wall next to the numbers.
From here head up the top of the nearby tower and take the zipline down, then climb up the cliff and swim over to the buoy before diving and collecting the treasure from the back of the boat to complete the quest.