In Ithaca, New York, in 1929, John Alden tells a gathering of academics that he is a visitor from the twenty first century--that he washed up on their campus after tumbling over a waterfall in the year 2010. He further claims to be a retired New York City detective who went over Ithaca Falls in pursuit of a serial killer. The revelation sets off weeks of trepidation in the storied hills of Cornell University as the strange visitor tells...