Henry, Jessie, Violet, and Benny are on a train from Boston to San Francisco. Even though they used to live in a boxcar, this is the first time they've ridden a real, moving train. And they find a mystery to solve even before they leave the station. Is someone trying to steal a young woman's portfolio? Could it be the porter? Or is it the tall, bearded man who always wears sunglasses -- even at night? What's in the portfolio, anyway? Can the Boxcar Children solve the mystery in only three days and three nights, before the train arrives in San Francisco and all is lost? - Back cover.