The East Coast of the United States - 1871. "Sea monsters" are sinking ships up and down the Atlantic seaboard. PRESIDENT ULYSSES S. GRANT, enraged that his navy is helpless in the face of this onslaught, is forced to ask for assistance from the notorious CAPTAIN NEMO, in Federal prison for war crimes and scheduled for execution. Grant returns Nemo's submarine, the infamous Victorian Steampunk marvel NAUTILUS, and promises a full Presidential pardon if Nemo hunts down and destroys the source of the attacks. Accompanied by the beautiful daughter of Grant's chief advisor, Nemo sets off under the sea in search of answers. Unfortunately, the enemy may be closer than any of them realize.