Weevil

Best answer as chosen by Asker / Ratings
First, you need to complete the Woodfall dungeon, as you need the bow to make your way up to the Snowhead mountains. You then need to complete the Snowhead dungeon, as you need it to be spring at the Goron village. Enter the store that was frozen before, and complete the Powder Keg tutorial. You can now purchase Powder Kegs from the bomb store at Clock Town (with the Goron Mask).

Use the Powder Keg to blow up the giant boulder blocking the path to Romani Ranch (before the last day) and help the girl with her "alien" problem.