Cabana Deed At Windfall Island:

Speak to the schoolteacher, Ms. Marie. She will tell you a story about the boys that do not want to attend her class. Speak to the four boys outside (a.k.a. the Killer Bees). Agree to play their game of hide 'n' seek. After catching all of them, they will give you a Heart Piece. After you play their game, talk to the schoolteacher. She will tell you of her obsession with jewelry. Give her twenty Joy Pendants and she will give you her Cabana Deed.