The plot of the game is based around William Drake, the last remnant of the old aristocrat, industrialist family. After the bankrupt of the familial industry and the death of protagonist's grandmother, young William Drake sets sail for open seas on the last freighter of the Drake Enterprises. The cargo ship soon gets taken over by a group of mercenaries, while Drake rushes out to answer a distress call. While sparing his life, the group of seven invaders seize control of the boat, thus binding Williams' fate to their own. The protagonist sees no other options than to unite himself with his new crew, hoping for the best.
Source: Wikipedia, "Aquanox," available under the CC-BY-SA License.