Set against the background of the fictitious town of CASTLE' Brazil. The OS MORTOS FESTIVALE' celebrating the annual ZOMBIE WALK is in full swing. The biggest weekend for this small tourist town. A small fishing/diving boat "The Lyric" and her captain "Patrice Fisher" are commissioned for a four day fishing trip by a group of "lawyers". Once at sea, they realize that the "lawyers" are mercenaries, lead by "Fabian Carrillo", who are on a seek and destroy mission looking for a naval ship that has been out of communication for weeks and suspected to be in non-international waters. When they find the vessel, the mercs find that the crew has been infected with a virus that turned them into Zombies. Their new mission is to stop the spread of the virus. To do this, they must board the USS REVERE, plant explosives on her watertight hatches, and sink her. Their only problem; the hatch is 7 decks down, partially flooded, and there are 125 Zombies on board.