There may not be many side-quests, but they’re all good ’uns. Here’s how you smash them into a solved pulp:
Fishing Rod
Travel to Bannan Island and talk to the Wayfarer in his hut- turns out he’s got a thing for mermaids. To find the ‘mermaid,' leave the hut and kill all the monsters on the western half of the isle. Head towards your boat and the mermaid will be in the water. Hit her with the boomerang and return to the Wayfarer. Huh? No mermaid? Go and talk to Linebeck and return to the Wayfarer again. He’ll give you the fishing rod.
