In 1870 the infamous Tammany Hall racketeer "Boss" William March, who ran New York City politics through a system of strong-arm favoritism, caught wind of a project to create a museum of paleontology in Central Park. Because he couldn't figure out any way to scam any profits for himself out of the deal, and because his religious convictions wouldn't allow him to believe in "antediluvian monsters," he had the museum's models and sculptures demolished. The models had been built by Benjamin Hawkins, a famous British sculptor who had overseen construction of a similiar exhibit some years earlier for Queen Victoria's Silver Jubilee.

Young Orville Leblanc is a would-be artist whose banker father forbids to have anything to do with such frivolity as painting and drawing. Through a piece of luck, Orvy goes to work in Benjamin's studio during the fateful summer of 1870,and finds himself enmeshed drawn into an exciting and dangerous adventure.