When some Camden, New Jersey drug dealers get blown away by a smooth operator who's impersonating a cop, the case falls to bleary-eyed, wisecracking police vets Macuszak and Whitcomb, But before they can even begin, an FBI team swoops in, headed by bossy and humorless Roger Sorenson. He identifies the perp as James Sullivan, an attorney who dropped out of sight a few years ago and has been taking out criminals ever since. Police sergeant Stacey Smith inadvertently crosses paths with Sullivan when her undercover stint as a prostitute interferes with Sullivan's attack on some militiamen at a casino. Sullivan eludes capture and Stacey lands on Sorenson's team, though he considers her far from an equal partner. In bits and pieces, it's revealed that Sullivan's vigilantism stems from criminal activity of his former colleague Dennis O'Brien, whom Sullivan blames for the death of his wife Ginger. O'Brien uses his law firm to launder dirty money and keeps a tank of deadly sharks that lends the title its literal dimension.