The heroes are Null, a man with neither feelings nor humanity, a near automaton of vengeance, and Boyd, a woman who has lost everything in her life that meant anything to her, ruled by guilt and a sense of duty at war with her compassion.

Criminal psychopath Dr. Benway, who saved Null's sanity with an illegal, experimental therapy, has invented a new designer street drug delivered by a stick of gum. His plan is to distribute the gum, known as "the Chaw", to Boston and Cambridge clubs for free to create demand. But when the Ecstasy-like sensual pleasure wears off, the after-effect is a murderous, violent rage.

Micmac Indian high-rise construction "edgewalker" and mob enforcer Filmore Lakeworry, known as "Lumpy" for his short, thick stature, forces a partnership with Benway at gunpoint. Null and Boyd set out to stop them, but Null changes his mind as the Chaw restores to him some of his lost humanity and Boyd can't charge Benway because his specially concocted drug isn't illegal.

Null falls into a short-lived, drug-driven romance with Boyd, ending with him tearing up the streets with extreme violence that ultimately installs him as the "Meth King" of Boston.