The Quest is the name of Mark Blackburn's boat. Mark, a marine archaeologist, is joined by John Morgan in his search for wrecks of sixteenth century Chinese trading-ships submerged deep in the sea off the Gulf of Thailand. When a local fisherman brings a piece of rare porcelain to his boat, Mark is thrilled and can hardly wait to go to the place where the fisherman has netted the extremely valuable artefact. But John and Mark's enthusiasm turns to horror when they find the fisherman drowned the very next day.