If you travel to Nashmau by boat, exit the dock area for a cutscene with Totoroon. Otherwise, walk to H-9 in Nashmau to receive the cutscene.
Choose the top option, "No, let's keep trying!"
If you pick the bottom option by accident, you don't have to warp back to Whitegate to restart the event. Stay in Nashmau until next game day and return to the dock area, and you will have another chance to choose the top option.
Choose the top option, "Leave it to me!"
Once again, if you accidentally pick the wrong answer, wait one game day and try again.
Take the east exit from Nashmau and investigate the ??? on the east coast of the pond. It's in shallow water by the shore at I-10 in Caedarva Mire, and there is no aggro on the way for a level 75 player.
The correct ??? is near the lily path to the island, not the one on the island. The correct ??? near the path to the island will give you a cutscene where the other will just say "it looks like someone slipped here..."