Go to the hut and talk to Big Mike. Ask him for the shell collection box and then talk to his daughter Pua if you need to trade for anything. If you give Big Mike 6 Uluas, then he will take a break. With that, he'll give you a Zippy bait and a fish basket to catch fishes with.
You'll be met with an earthquake and woof, then afterward go talk to Pua. You'll need to create necklaces in return for fish bait. You need to go fishing to grab those Uluas that Mike wants. Anyway, just click on the bait jar, cast the rod. when the bobbin sinks, click on it immediately to get your fish.
Give Mike the fishes and then go back to Pua. At this point, Mike will drive away. This gives you time to search his office for clues. Now check out the calendar and read the note about JK and grab the key from there. Then, unlock the door behind the desk using the key you found. Now search the drawers and look for the map. Three Finger Rock will be in the map, with the coordinates, N 10 24'42 W 155 9'1 The moment you give Nancy the coordinates you'll be clobbered.