you get the grappling hook by following the story line, when you get to the dragon roost island the cheiftain requests that you speak to medli, when you speak to medli she gives you something to give to her brother then asks you to meet her in the dried up lake pool wateva, when you do you lob her up onto a ledge dhe says dont folow me and dont tell dad, so you follow her and when you get to the top you save her life and she gives you the grappling hook