In his latest case, Alo Nudger is qpproached by Adelaide Lacy with a most unusual photograph. It is of the historic Arcade Building, and was taken at such a slow speed that only perfectly still objects appear. Oddly, the image of the assistant city comptroller, Virgil Hiller, appears in the photo. He is seated at a desk with his pen poised. But why has he remained so very still for so long? Now Virgil has disappeared with Mary, his secretary and Adelaide's sister, and half a million dollars in city funds...