First you need to go to Canalave City. Then go to the sailor. There is a house by there go
in talk to the sailor. Next go in the house and talk to the kid in the bed. Then talk to
the lady the sailor will come in. Then go outside the sailor will ask if you want to go to
Fullmoon island go there.Then you can find Cresselia.Once you do talk to her and she will
go away take the item she left and take it to the child in the sailors house.