Walt Duffy was a world-renowned ornithologist, outdoorsman, and nature photographer who spent his life traveling and taking some of the most highly regarded photographs of birds in their natural habitats. Until, that is, over a year ago, when a climbing accident left him a paraplegic. Now he spends his time in the backyard of his brownstone in Boston, with only his dog and his teenaged son, Ethan, for company.

Brady Coyne, Walt's longtime friend and attorney, handles his routine legal affairs and is asked by Walt to deliver a set of Meriwether Lewis letters to a rare-book dealer for authentication. Shortly afterward, responding to a call from Duffy, Coyne stops by after work only to find Walt dead - murdered - in his backyard. Robbery is dismissed as a motive when the only thing that turns up missing is Walt's laptop. Equally disturbing is the fact that Ethan has vanished without a trace, any sign of struggle, or any clue as to where he may have gone. There is also evidence that Walt was somehow involved in a notorious ecoterrorist group that is currently taking deadly action around the Boston area.

With the FBI and the Boston police watching him closely, the ecoterrorists escalating dramatically, and Ethan still missing, Brady finds himself in the center of an increasingly dangerous plot. As the death toll mounts, Brady realizes he has to find Ethan and unravel the complex puzzle before either of them becomes the latest victim.