Judgment on Erebus is narrative nonfiction at its most compelling and unsettling.

Commanded by one of Air New Zealand's most meticulous and cautious pilots, a sightseeing airliner inexplicably crashes into an active Antarctic volcano in broad daylight, causing the world's fourth-worst aviation disaster. The New Zealand government's Office of Air Accidents Investigation soon publishes an official report attributing the disaster to pilot error. Skeptical, an aroused public demands an "independent" official inquiry. Realizing that he badly needs a second investigator to confirm the first one's findings, an imperious Prime Minister selects for the post a distinguished High Court judge he believes will be a team player.

After conducting his own extensive inquiry into the crash, though, Justice Peter Mahon reaches a verdict on the cause(s) of and culpability for the devastating loss of life on Mt. Erebus that is totally incompatible with the government's earlier in-house report. All hell breaks loose. One of the two official investigators must be gravely mistaken-or lying-but which one and why? Years of political, legal, and judicial pyrotechnics commence to answer that question. Meanwhile, a stricken nation mourns its 257 dead.

Sheehan takes a fresh look at Mahon's evidence for concluding that the national airline itself was responsible for the tragic loss of life, which the government immediately tried to cover up with a well-organized, multi-tentacled, multi-phased, and aggressive attempt to pin the accident on the well-respected dead pilots. She also movingly relates what befell the judge after an enraged Prime Minister turned on him. This twist gives a superb political and legal thriller its moral center: a Goliath-against-David struggle over the truth.