Jim Perkins' mother dies of cancer when he's fifteen, leaving him and his father and big brother not just grieving but at a loss as to how to go on; she was central to the family, and now they're paralyzed.  But while Jim struggles to get up the energy to go back to school, and Dad begins secretly hitting the bottle, brother Frank wrestles with another problem, one that soon overshadows even Mom's death: the mysterious and violent history of Woodsen Lake.

Named for a pioneer trapper, the lake has been in Mom'sfamily for a hundred years, a source of pride but also of obligation, as each generation is sworn to keeping it at all costs.  When Dad sells it to pay for Mom's futile cancer treatments, she is furious and, from her deathbed, makes her oldest son, Frank, promise to get it back.  Against his will, he agrees but how?  The businessman it's sold  to, Mr. Bunsen, plans to "develop" it, to line its ancient shores with luxury apartments and condominiums.  He has no appreciation for  the lake's history or its importance to Jim's family, only its profit  potential.

He has a daughter, though, a wild pretty girl named Gina, and Frank sets out to woo her in hopes the old man will make the  lake a wedding gift to them.  When that doesn't work, he decides  the only way he can get it is if Gina inherits it.  Of course, that's not  possible while her father is alive.  In his desperate state of mind, haunted by his dying mother's pleas, Frank hatches a plan: standing  on one side of the lake, aiming across at the Bunsens' backyard, he'll shoot Mr. Bunsen as he sits in his lawn chair reading the Saturday morning newspaper.  He tells only one other person what he's going  to do: his little brother.  Not sure whether to believe it or not, and afraid to tell anybody in any case, Jim finds himself the only one with a chance of stopping the murder.

But while he's trying to keep this awful secret, and also keep it from coming true, Jim is finding out more than he ever wanted to know about the lake, mainly from Grandma, who is obligated to pass the story on to someone in the next generation.  In fact, she passes on more than just information and lore: she also hints at her growing suspicions that the family's relationship to the lake may not be as clean and pure and blissful as it seems.  She wants to tell Jim what  she's thinking, but he doesn't want to hear it.

At the same time, though, Jim hears about the lake from another source: the daughter of the only Indian man in town, both descendants of the tribe that was chased away after a fire that burned up Abe Woodsen in his cabin those many years ago.  She has heard a story from her own father, who heard it from his: she blames Jim's family for her people's plight and hints that Abe Woodsen wasn't killed by Indians after all.  At first Jim is annoyed, even angry: he doesn't want to know anything about "that damned stupid lake" that has caused his family so much heartache. Gradually, though, he begins to think that the answer to stopping Frank may lie in finding out the truth about how his family came to own Woodsen Lake and why it's such an obsession with them. What he learns is what gives this novel its name.