"Many traders have come to this island to sell their wares. One of them is Merchant Zapang. He seems to have run into a little problem, though, and has requested help. This will be your first taste of heroic action! Go help him!"
After accepting the quest, head south and up one flight of stairs to Merchant Zapang.
"Have we met? Oh, you're Gildas's latest trainee. Excellent! I desperately need your help!"