Mark Aaron, a historical researcher for Nora Corporation, is summoned to the office of the president and C.E.O. Instead of taking the offered promotion, he leaves for a vacation with his wife. A plane crash begins a five-hundred-year odyssey through time, space, and history. To save his wife, his unborn child, and humanity itself, Mark and his companion Jane, a Gamma class android, must travel to the year 1842 to prevent the premature assassination of Abraham Lincoln. Along the way, they become enmeshed in the politics of Springfield, Illinois; encounter Abraham Lincoln, Mary Todd, and James Shields; and create controversy themselves by applying 21st century ethics to 19th century problems.